Change the background color with this code.
Set the background to transparent.
Use a image as background.
By setting the background-attachment to "fixed" you make sure that your background-image will stay fixed instead of move when you scroll the page.
With this code you decide if the background image is to be repeated (tiled). If you have a small image with a pattern you might want to repeat it but if you use one large image for the background setting the tiling to "no-repeat" might be a good idea. "repeat-y" will make the background repeat only vertically while "repeat-x" will make it repeat only horizentally.
background-repeat: repeat;
background-repeat: repeat-y;
background-repeat: repeat-x;