One of the most oft questions I get asked on my blog Lost & Taken isn't about the textures, it's “How did you create your subtle background image?”. It's actually a pretty quick process in Photoshop, but I've taken the liberty of putting together 9 different seamless noise-y patterns to help save you guys a little extra time. The patterns are a combination of noise and grunge, with some of them coming from photographs and others being generated by the computer. They're perfectly seamless and will work great for website backgrounds and many other projects.
If you're looking for a good way to put them to use check out what's tagged with “noise” on Dribbble. There are all kinds of awesome designs on there that utilize patterns just like these.
I've included nine high-res .JPG files that you can edit/modify to your liking. I've also included a Photoshop .PAT file if you're in need of a quick pattern fix. Both the .JPG and .PAT files are included in the download at the bottom of the post. Enjoy!