I'm trying out Windows 7 on an older computer with an unsupported graphics card. It turns out win7 (build 7077) still supports older 2K/XP (!) drivers, in this case Catalyst 6.11 for my Radeon 9200. It will fail when installing the package, but after that you can do a manual driver update and pick the location (navigate to the 2KXP_INF folder). I did some research online, and all source claimed there was nothing that could be done. This method improves "Standard VGA driver" with 16MB memory to the attached image; I can also change my refresh rate now. It of course won't support AERO but it's definitely an improvement.
Vista and Win 7 did this for an NVidia GeForce Go4200 32MB onboard gfx card on my laptop. I used the Win2000 drivers from the Dell website ... it was the only way to get directx acceleration working. Of course, no aero though ,but at least Media Center in Win7 runs with gfx acceleration (had to disable media center's directx checks though).