Help on Random animation

Dear all,

I am not an expert in design and animation but I need to build something and would lilke to know the best way for it.
I have an application which build a bunch of ellipse object with text inside. What I need to do is when I strat my application, all those ellipses should float on screen area giving a nice moving effect.

What is the best way to do that, in order that those object permenently moves around and inside the 1024 by 768 relosution screen.

Any tips or sample will help
regards
serge