Fade/Alpha help

I am trying to split my site into three sections, and I am trying to do this by having the home page contain a flash animation that would work like this:

[Pic1a] [Pic2b] [Pic3c]

(assuming you have a pic a,b,c for each number)

Hover over Pic2:
[Pic2a] [Pic2b] [Pic2c]

I hope you got that diagram. Anyway, I want it to crossfade into the different images. And if you hover on another picture it fades seemlessly without jumping back to no fade at all.

Does anyone know where there is a tutorial that can help, or is there anyone who just knows?

Thank you,