Lion Brand Yarn - Great yarn and TONS of great free patterns!
Crochet Pattern Central - links to just about every crochet pattern online, organized by type! Very handy!
Stitch Guide.com - Forgot how to do that stitch? Go here for instructions and VIDEO CLIPS!
Free Patterns.com - Lots more free patterns of all kinds (in .pdf format)!
Other Fun Links
Homestar Runner - The funniest flash cartoon site ever. I especially recommend Strong Bad's emails. Funny funny stuff!