h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

There are also lots and lots of websites which will give you further information on where to find out more.

Try these to get yourself started: (these are all UK based)

http://www.witchcraft.org (wiccan organisation, events, articles, forums)
http://www.avalonia.co.uk (excellent articles, events listings, forums, home of WWL and contacts for the UK)
http://www.ukpagan.com (news, forums and links)
http://www.wiccauk.com (news, forums, events and links)

That would be a good start, you can also visit the USA based website http://www.witchvox.com which contains hundreds if not thousands of contacts, events and such.

Have fun!

My recommendations are Prof Ronald Hutton's 'Stations of the Sun: A History of the Ritual Year in Britain' (the most comprehensive survey of seasonal customs in Britain yet in print, and it also has a chapter on how this ties in with modern Paganism); his 'The Triumph of the Moon' ( a very cool history of Wicca through the available sources; he even gives those who refused or evaded his requests for evidence afer they'd claimed they had it the benefit of the doubt, simply stating that without evidence their claims could not be proved); and his 'The Pagan Religions of the Ancient British Isles' (synopsis: without native written evidence, we can't be sure, but here's the physical evidence we've found and some interpretations).

Love, too, Robin Brigg's 'Witches and Neighbours' (all about the European witchhunts); Kors and Peters' 'Witchcraft in Europe, 1100-1700: A Documentary History' (how did Christianity go from believing that witchcraft essentially didn't work to seeing it as the major threat to humanity?); Carlo Ginzburg's 'Ecstacies: Deciphering the Witches' Sabbath' (interesting stuff on hallucinogens, Church doctrine, and Italian peasant revolutionaries); and Keith Thomas's 'Religion and the Decline of Magic' (attitudes to magic and religion in the Renaissance-Enlightenment period).

And on Wicca itself, I do like Starhawk, for all she's looked down on by some as too feminist; Janet and Stewart Farrar; and Judy Harrow.