This was a real headache for me once. I found a few methods one being;
http://64.233.183.104/search?q=cache...ient=firefox-a
But in the end it just ended up looking bad one way or another. In the end I went with 'wrapping' (if you get me) the page rather than just a repeating background image (
http://www.frombasics.com/forum/)
All depends how much work you want to put into getting it to look right
Thanks,
Mat.