Noticed this on Slashdot, here's a quick copy & paste from their post:
For those of you who bought an nForce2 motherboard with the hopes of doing a bit of linux gaming on it, I'm sure it was a pretty hard let down to find out there was no AGPGART driver for the nForce2 – until now. nVidia has finally released a kernel patch for the 2.4.20 release that is now providing GART support. Perhaps this means that nVidia is re-thinking their closed source-isms in favor of a more open policy in the future. A note on AGP 3.0: Note that AGP 8x mode is not available in 2.4.xx series kernels. If you find that X will not start, try disabling 8X mode in your BIOS. AGP3.0 has been implemented in the 2.5 series.