As with all destinations, a good guidebook can be a far more efficient and reliable way of mugging up on the best and worst about a country. Websites are only really useful for finding out about forthcoming events and getting up-to-date information about places to visit.
Some of the country's state tourist offices have their own sites, although the prose on some of them is rather overdone. Himachal Pradesh, for example, promises "lush river valleys surrounded by snow-capped peaks and dense forests that echo with birdsongs evoking enchantment and delight." But if you're unfamiliar with this part of the world, you might find it useful for background.
If you need to find a soulmate for your adventures, try the Travel Companions' Database, which aims to put you in touch with like-minded people. My request for a male non-smoker aged between 25 and 30 to go travelling for four weeks in August drew a blank, but they claim the set-up is fairly new. Perhaps it just needs time to build up a critical mass.
The Indian government's home page
India search engine.
Index of state tourist pages.
The Travel Companions' Database.Reuse content