Ha, clicking that link was a trip. Unlike et_synecdoche's (perfectly serviceable!) code, I used inline CSS:
Breakdown: • the bgcolor in the initial TABLE tag is going to be covered by your pattern background, but I specified one in case someone has graphics turned off or my image stops working. • background-attachment:scroll is going to make the image move as you page down; if you want the image to stay in a fixed position replace 'scroll' with 'fixed'. • TD BGCOLOR needs to be specified in every cell; it's your solid color against the patterned image. Cellpadding and cellspacing are arbitrary numbers, but the bigger your cellspacing, the thicker/larger your background image will be.
I hope that helps! If you have Firefox you can always just highlight the area of code you want to look at, right-click and choose "View Selection Source". :]