What would JR Hartley make of it all? Hartley, you may remember, was the old buffer who creaked round second-hand bookshops in search of Fly Fishing in the famous Yellow Pages TV commercial. Now he has been resurrected in the ad campaign for the new Amazon.co.uk internet bookstore. And, as the ad implies, if Hartley could cast a line today into any such site, he would find hundreds of fly-fishing titles to choose from, ranging from (at Amazon) Life is But a Stream to Another Lousy Day in Paradise, not to mention several titles by one JR Hartley. Bookselling is one of the internet's commercial success stories, and there is a host of new UK launches trying to cash in. The big advantage of internet bookshops over their high-street-bound rivals is scale: most normal bookshops can only stock around 40,000 titles; an internet site can carry a million.

Amazon remains the standard and, now that you don't have to use the US parent site (Amazon.com), delivery times are down to a few days. The site's tone is chatty and inclusive, and one of the best features is the usually reliable readers' reviews: someone from Bradford warns that Joseph Kanon's Los Alamos has "one eye on the plot, one eye on who will be cast in the movie version". The Internet Bookshop, recently bought out by WH Smith, has the same basic format as Amazon, but is somewhat less polished: the word "hilarious" is used three times on the opening page to describe featured new comic novels, none of which look at all hilarious. As with all the sites there are eye-grabbing discounts, but with the usual drawback of delivery charges: the Internet Bookshop has a minimum of pounds 1.95 in the UK (the same as Amazon). The other big new entrant into the UK is bol.com, from the German publisher Bertlesmann. The design is corporate and austere - Germanic, some might say - but the content is good, and there are nice touches such as an interactive Gift Ideas section.

On a smaller scale than these outfits, but much classier, are a new offering from Penguin Classics, and the Waterstones online store. The latter is tasteful, simple and not an airport novel in sight. It also has a Books of the Century guide (find out what you should be reading). Penguin Classics is similarly upmarket, but restricted to the imprint's 1,600 titles. It also has reference links to related sites, downloadable Classics screensavers and in-depth articles on featured titles, which on a recent visit included Eugene Onegin and The Communist Manifesto - sorry, JR, nothing on fly fishing. Jonathan Dyson

Amazon.co.uk; bookshop.co.uk; bol.com; Waterstones.com; PenguinClassics.com