Flutterby™! : Wussy question

I'm heads down in work and could figure this out for myself, but getting it right cross-platform and all would suck, so... What I want is a little JavaScript to let me put several rollover hot-spots on an image, each of which displays a <div ... at that location. Specifically, if I've got a map with hotspots, I'd like to be able to rollover those and display alittle thumbnail with a description and some links. Should be easy, although I know that there are some cross-browser positioning issues, and I'm too far in to C++ and scene graphs right now to want to spend the hours it'd take to get it right.