This plugin works out of the box, and does exactly what it says it will do.
It has options for controlling the position of the image: repeat, horizontal position, vertical position, and fixed vs. scrolling. It even has the option for selecting a background color.
What's missing is the one feature I need, which is the option to scale the image to fill the entire page. I was able to remedy this with a single CSS statement, but it would be nice to do it with JS for greater browser compatibility.
It's a great plugin, nonetheless!