Hangin’ Around the PatternCooler
If you are in need of a background pattern for your website, PatternCooler is likely to have what you want. There are thousands of backgrounds available for download and are freely available for your use: "All artworks on this site can be used freely on blogs, MySpace profiles, Twitter, mobile phone wallpapers, and non-commercial web projects" (PatternCooler).
The website offers the ability to customize the patterns and backgrounds to your liking using the Seamless Pattern Color Editor (example). This editor, as shown below, allows you to pick a pattern and change the colors using a color picker or hex codes.
Along with the available patterns for editing, there are over 20,000 prebuilt patterns available for download from the User-Colored Seamless Pattern Background Library. Technically you can edit these as well, but they probably have a pattern you like in this collection. Once you have decided on a pattern, you have the option to download and/or view the pattern.
You can get a glimpse of what the backgrounds that are offered will look like simply by viewing the front page. The front page uses one of their patterns as the background and changes with each refresh of the page. Along with the automatic loading of their patterns, you can change the background to whatever pattern you want to see. The view option allows you to see it on as the background on the current page or on a blank page.
Be sure to check out all of the patterns they have to offer. Chances are you will find one, probably multiple, that you like. If you like the service offered, consider donating to help out.