As mentioned in my previous post, the Seti@home guys have released their CUDA-based application. After upgrading the hardware I spent most of today experimenting with the app_info settings.
It needs a CPU to "feed" the GPU, so it runs as 3 cpu tasks + 1 gpu task at a time on my quad core machine. Below is a screen shot of it running a Seti multi-beam work unit on the gpu.
This is a screen shot of the temperature utility for the graphics card, showing its getting a work out.