Patterns made easy.

Bgpatterns.com is a great, easy to use website. They offer a pattern generator that is completely customizable. You can chose from a selection of images and colors; even textures. I even used a pattern I made using this site for this header! This is a great tool for every web and graphic designer. I recommend it to everyone.
Even if you're too lazy to make your own, you can browse through the Top Rated and Recently Added categories, and probably find an awesome pattern there.