Crochet Pattern Central – Thousands of links to free crochet patterns.
Ravelry – Good site for searching for patterns – lots of pictures and lots of patterns.
Attic 24 – Excellent crochet blog with free patterns.
The Crochet Doctor – Great for hints and tips.
Easy – lots of great free patterns.
One Flew Over – great blog.
Antique Crochet Patterns – Free vintage patterns.
Knitting Paradise – Fantastic forum for knitters and crocheters. Loads of friendly people who are always willing to help you out or give you advice. Includes topics on just about anything you can imagine.