XFree86 4.2 has drivers for that onboard video card on CVS. http://www.xfree86.org/~dawes/845driver.html
The onboard sound card is described as ADI Ondboard audio, and uses the Soundmax driver on Windows. Other audio cards that uses that chip work on linux using the i810 and AC97 drivers in recent kernels.
So, probably your 260 is linux-compliant.
BTW; We are probably going to get 260's at work (using W2K) since the GX400 are not being made anymore it seems. Are they nice? I really liked the GX400.
Fixed the link -- stryder144