Well, currently there are only pre-built modules for 2.4-series kernels in the sarge (and sid, now I've checked), but the maintainer, Randall Donald, has his own repositories which you will find links to on his Debian/NVIDIA packaging homepage
. I believe there are modules for 2.6.7 there. Alternatively you could just install the kernel headers for your kernel and build the modules yourself. If you choose to do that, then the docs for nvidia-kernel-source cover it pretty clearly.
EDIT: Poster posted a followup before I posted this, though I think this is still useful.