Shane came across these (nice find):
I just noticed this while browsing around and figured I’d pass it on. There have been several posts on (CSS) tabbed navigation menus using the “Sliding Doors” technique originally showcased on Zeldman.com.
Here are 11 free ones you can use – just pop them into a content editor web part and you are all set.
I have one on my site that my buddy did.
My only two cents to anyone who wants to do this, be sure your images are teeny tiny in size, or you will end up with a flicker every time the user mouses over the tab as the site loads the hover image. CSS only tab navigation is another way to go and omit the images entirely.