CATalyst Council - Offers videos and articles on cat care, health, nutrition, etc.
Frequently Asked Questions about Cats
Why does my cat eat things that aren't food?
How an I introduce a new cat (a stray that I found) to my household of one very, very spoiled cat, who has "ruled the roost" alone for the past four years?
Cats – Articles on everything from cat nutrition to litter box behavior, and a forum where you can discuss your ailurophilia with others of like mind. From About.com
Cat Fancy Magazine – The feline library and "cats on the Web" links are particularly good.
The Cat Fanciers' Association – Information on cat shows, care, and breeds.