Yes that's right, some guy at the 2K Forums is working on patch to have Bioshock run on SM2-based video cards. The game as released would not play on SM2 video cards such as the x800/700/500s and 9800/9700/9600 cards. One guy in the thread managed to get it running on a 9600PRO. Nvidia's FX series is out of the question as SM2 support was gruesomly poor (many people in the thread saying they couldn't get it to run on their FX series cards). There's some screenies of it running on an x800:
Here's the link to the thread (with download for patch!!):
Making Bioshock Work with SM2.0 Cards! (Work in progress) - 2K Forums
Glad I found this, can't wait till' a stable patch is released to work with my OC'd 9600XT B)