The world yesterday marked the 20th anniversary of Elvis's death. A chance to remember that music can take you to the heart of a country. By Jasper Wynn
Why is music like food and sex? Is it because one is often prepared to travel further afield in search of something a bit different, a bit special? Though the general idea behind music - and indeed food and sex - is pretty universal, it is the variations that people around the world come up with that add spice to the recipe. All music relies on banging, blowing, strumming and hollering, but not all music sounds the same - certainly not when you travel to find it.

Actually, these days you don't have to travel far to hear the global soundtrack. With record companies like Hannibal, World Circuit, Globestyle and Real World issuing CDs by some of the most intriguing of the planet's musicians, and with everything from Pakistani gawwaii singers to Colombian cumbia proving hits at Britain's summer festivals, world music is rapidly becoming the music next door.

You can hear everything that's on offer via a trip to a specialist record shop, or a weekend spent wearing a tie-dye tee-shirt in front of Glastonbury's World stage. But the odds are that you'd appreciate the same sounds even more in their natural habitat. Whether your musical tipple is Cuban son, Nigerian juju or Hungarian csardas, there's never been a better time to pack your Rough Guide to World Music, jump on a plane and head off on a musical safari.

You can find music in the most unlikely of places. A bunch of Tehrani students once showed me which pre-revolutionary songs were banned in Iran by singing them in their entirety, thumping out the rhythms on buckets. But some countries are just plain rootsier than others. My own shortlist of sure-fire destinations includes Spain, Morocco, Cuba, Ireland, all of West Africa and large parts of India. But, wherever you go, you'll still need a game-plan of sorts to track down what the locals listen to and avoid the diddly-dai-day, 'Guantanamera', beads-'n'-feathers whimsy of the stuff got up for passing tourists.

Ireland's traditional seisiuns illustrate the difficulties of tracking down roots music the world over. Good musicians may spend the early part of an evening earning a bob by playing a tourist gig in a theme bar. An hour later they can be stuck into a serious session in a pub down the road. There the ballads so beloved of the 'leprechaun' shows will be few and far between: instead the emphasis will be on the jigs and reels of the traditional repertoire.

The problem is that the hottest seisiuns and the mightiest craic tend to be nomadic, moving on fast enough to stay one pub ahead of their celebrity. Word-of-mouth is often the only advertisement of where the best players are gathering. In the summer, when musicians take to 'rambling,' the epicentre of Ireland's traditional music scene is equally likely to pop up at a crossroads pub in Mayo, a Cork horsefair or a bar in the backstreets of Tralee.

The same spirit of independence is found in Spain's flamenco scene. Since the explosion of nuevo flamenco blew new fire into the tradition in the 1980s, Madrid has become a better bet than Andalucia for nights of spontaneous duende. The bars in the streets off the Plaza de Lavapies are where many of Madrid's jobbing flamenco musicians gather after their paying gigs. This often means no more than shouted flirtations and even louder disputes, but these can easily ignite into the sex-and-violence fusion of guitar, voice and zapatear, the percussive explosion of the dance steps.

In these informal outbursts, or juerqas, the gap between audience and performers is blurred. There is a potential disaster in this for the interloper. It's easy to be fooled by the seemingly simple art of palmas into clapping along to the staccato clatter of a sevillana or buleira. This usually has the same effect as pulling out your bongos at a Malian kora recital, or singing a couple of verses of 'Rule Britannia' at a North Donegal traditional session. Don't do it.

In cultures even more traditional than those of Spain and Ireland, the line between audience and performer has never been fully drawn. Music in Africa and Asia is as much about ritual as entertainment and, as such, directly involves everybody within earshot. In Morocco, as elsewhere, music gives a framework to life's dramas, making the weddings, funerals, circumcisions and other rites of passage understandable.

This is one of the very real rewards of hearing music in its proper setting. For the outsider, it can be a fast track into a country's emotional heart. The happy truth is that we all have a working knowledge of rhythm and melody, however rudimentary. Most of us are going to understand and appreciate a country's soul through its music long before we fathom out its literature, theatre or politics.

To actually track down music in Marrakech, Bombay or Caracas is never that difficult. David Flower, whose company SASA music tours musicians from Mali, Cuba, Spain, India and Kenya throughout Europe, sums up the technique. "Follow your ears, walk around the streets and ask people where you can find music. Talk to guys on food stalls, to guys selling bootleg cassettes, to taxi drivers. Especially to taxi drivers."

The taxi driver connection is as universal as it is logical. Not only do they know everybody, but they spend hours listening to their car radios and cassette players. In Morocco a shared cross-country taxi ride is a crash course in the eclecticism of the Maghreby tradition. Passengers often produce their own tapes, so that a chorusing of Berber ahidus can meet the courtly strains of Arabic-rooted andalous, and the zkir of Sufi brotherhoods reaching for God through repeated chants jostle against the African rhythms used by Gnaoua to expel djun from the possessed. And the enforced intimacy of eight people stuffed into one car can often lead to an invitation to a wedding or some such hafla - the catch-all word for a party - at the end of the trip.

Of course being a guest on somebody else's big day means having to take on the full cultural package. Though the music may be your primary interest, any social event is always going to be more than a front row seat at an all-night gig. If you're attending a Moroccan wedding it's obligatory to eat chunks of mutton, sip endless glasses of syrupy tea and join in the congratulations when the bloodied wedding sheet is paraded past on a tray.

In Cuba, the social skills needed for acceptance into the vibrant world of son, nueva trova and rumba music are more familiar, especially to anyone who's already made the circuit of English summer festivals. Polite behaviour includes drinking large quantities of rum and non-stop dancing. Music has provided both the engine and the brakes for Cuba's revolutionary politics, giving an urgency to their rhythms and lyrics that is irresistible. Worldwide there are probably few countries where it is so easy to stumble over searing, heart-grabbing music, making Havana perhaps the most rewarding of destinations for a pot-luck trip.

When Cubans go out to dance they expect the music to keep going until dawn. And this is pretty much the norm around the world. Many West African dance bands, contracted to play for seven or eight straight hours, have "substitutes" who trot on stage and take over the instruments of any flagging musicians. Music played within a more expansive timescale than the usual British two-and-a-half-hours-if-you're-lucky mode has more room to work its magic. Even monotony can be part of the experience, lulling you into a trance-like suspension of reality. At a three-day festival of Southern Indian music in Kerala I was told by my host, Jose, as we sat on the sand watching a Kathikali play slowly unfold: "Just sleep if you get tired. Everybody else does, and somebody will wake you for the exciting bits."

When I showed interest in the elaborate make-up of the Kathikali dancers and the instruments of the musicians, Jose took me back-stage to take photographs. This was yet another bonus of being an enthusiastic foreigner abroad. Dancers and singers crowded around to explain the subtleties of their performance. One young lad had a request; did I have any Metallica or Madonna tapes? I didn't, but should have done. Being prepared with small gifts for the musicians whose hospitality and company you've enjoyed is easy. Music cassettes, recordings of the musicians themselves if you're carrying a tape-recorder or DAT machine, photographs of them (often gratefully used in publicity material afterwards), or any musical bits and bobs (guitar strings are highly desirable in Cuba and parts of West Africa); all fuel the karmic wheel of world music.

Of course, the present that would thrill even the most sophisticated and cosmopolitan of musicians would be a recording contract with Real World and the chance to headline at the next Womad festival. And if the players are good enough, they will probably get exactly that before too long. But in the meantime you can catch the next big things in world music on their home turf, well before Peter Gabriel has even heard of them. Just book your flight and get yourself to the music before it gets to everybody else.