Something that seems to be missed here is that this is not an entirely NVIDIA problem. AGP 3.0 support in 2.4.x is not very good, and may need some fixing prior to the nVidia patches being added in to the kernel.
However, if you know where to look to keep up with the bleeding edge AGPGART news, and are aware of this issue and the promises made here by Andy, you can put 2 and 2 together to see that the patch has gone from nVidia to the proper kernel developer; and seems to be waiting on a backport of the newer GART style in 2.5 to the current 2.4 tree. The whole thing gets compounded somewhat, as there is no "Official" 2.4 GART maintainer; the 2.5 GART maintainer hasn't been working on 2.4 yet.
2.4.21 would seem to be a really good kernel for nForce2 users. It already contains firewire patches, USB patches, a recent patch for explicit nForce IDE controllers, and will hopefully have a GART driver.
The only better news that could come from this would be nVidia patches for explicit nForce memory controller support and HYPERTransport support. (I guess nvnet kernel module would be too much to ask for, but generic support for the RealTek 8201BL would be good enough, as that's what's on my Abit NF7-S).
Patience, patience, patience. As the kernel guys say, It'll be out when it's ready. It is important to see that nVidia has made the right decision, and encourage them to continue in that vein. Flaming them because it isn't instantaneous is counterproductive.
IMO, instantaneous would have been a binary kernel add-on, which would have been a momentary victory, but a long term loss.
That's my .02, at least.