good news soylentgreen, there is a thing called dri ( direct rendering interface ) which gives you full opengl support for your card.
here are direct links to what you need:
make sure you extract those to DIFFERENT folders!
run the setup in common first
then run the setup in radeon
restart x ( or x.org )
and you should be good to go
(you need your kernal headers installed, there should be a pacage you can download for that..)
i get 700fps in glxgears with my igp 340m (64mb) and i get 48fps in quake 3 at 800x600 16bit color