I had it working for 64 bit too. It was just a little different. I had to use the *.tar files from Nvidia and again, the agpgart had to be a module and the amd64-agp was in the kernel. I also had to make the same changes as above to my XF86Config. I was also using Mandrake 9.2 AMD64 with a recompiled 2.4.23 kernel when i was doing this. Couldn't get it to go with the 2.6.0-test11 ( i know, lack of skill on my part ).
What kind of 3D programing are ya going to do?
Gentoo Linux-64, AMD64 Athlon 3200, Asus K8V Deluxe, 1 gig(3200 400mhz) ram, GeForce FX5200 128, HP 400i DVD+R+RW, HP ScanJet 2200c, Epson Stylus C84, JVC DRV3000U (firewire - usb), Kodak CX6330