The Complete Joy of Homebrewing– by Charlie Papazian: The quintessential guide to homebrewing by the godfather himself.
Brewing Classic Styles: 80 Winning Recipes Anyone Can Brew – by Jamil Zainasheff: Nothing but award winning homebrew recipes.
Designing Great Beers: The Ultimate Guide to Brewing Classic Beer Styles – by Ray Daniels: Advice on brewing from the Cicerone king himself.
Clone Brews: Recipes for 200 Brand-Name Beers– by Tess and Mark Szamatulski: Lots of great commercial clone recipes in this popular book.
Craft Beer– The consumer end of the Brewer’s association with lots of informative stuff.
BYO– Stands for Brew Your Own, dedicated to homebrewing. Also a great magazine worth subscribing to.
Home Brew Talk- Lots of great info and the best forum around.