GPU rendering

Hey everyone,

My first post here ;), so I’ll hope you can help me…
Some time ago I assembled my new PC (check signature for specs) dedicated to programming (DirectX & C++, Web), Physics simulation (i’m Physics Student) and maybe 3D modelling in the future. So I decided to install 2 ATi 4850’s for fast rendering. But…
2 Days ago I started with Blender (first result). But when I tried to render a project, I noticed that Blender only used the CPU and not the GPU!!! So when I tried to render a model containing > 300,000 vertices it took me more than 20 secondes to render :S.

My question: Is there a Blender plugin that uses the GPU for rendering instead of the CPU? If not, could anyone instruct me about the rendering engine so I can give it a shot using CUDE an ATI Stream?

Thanks in advance,