Hey man, I did this for a few spots on our site. I'm not really sure it's worth the effort, but basically anywhere that you use a series of graphics for links, you replace them with a single image and use CSS to properly style any text or hyperlinks over the image so that it all still looks like multiple element.
A good example of where you can best do this is where most blogs have Facebook/twitter/rss chicklets. If you're good with photoshop or another image editing program, it's not difficult. The hardest part is getting the CSS styling right.
I think i found a tutorial on google for this…