Change div on hover?, Looking for a script... Options

[fr0stbite]

So you know how you can code images to change on hover, to make them look prettier as links? Well, I had this idea that needs a little help.
You see, I want to be able to make "links" available on my header image... however, instead of having them lead you to some other page, it opens up a sidebar. The problem is, I'd actually like to have a different sidebar displayed when you hover over each different link (clicking on these "links" won't exactly take you any place, if you know what I mean. They're just there for hovering purposes).
I was hoping that the sidebars could be coded with DIVs, and include php and text and whatever else you can put into a DIV -- but how would I get it to change? An idea I had was to put everything into an image, then allow for that whole sidebar image to be changed when you hover over the link... but the difficulties with that are 1) you can't update it easily 2) that would involve a lot of link mapping 3) the links will look different from the regular text links.

So if anyone has an idea of what I can do to achieve this... mess... please tell me?