2d bitmap effects

I’ll be starting a multitouch project soon and don’t know where to start for the cool 2d effects.

Like colorful flame effects, or kind of clouds that move and change their color. Or like the typical mac screen saver…

I don’t really know where to start with that or how those things are called. I supose it’s all about coding bitmaps but to be honest I’m not sure at all.

Anyone has a tip on where to start investigating, some interesting url, or some tutorial?