To install the nforce2 platform drivers, you need to download the *.tar.gz file from NVIDIA, not the *.rpm file. Unpack the file by typing:
tar -xvzf <filename>.tar.gz
Then move to the newly created nforce directory:
cd nforce
Compile and install the drivers with (must be done as root):
make
make install
Now insert your network driver (as root):
insmod nvnet
To make sure the network driver is automatically loaded after reboot (as root):
kwrite /etc/modules
The text file that opens has a list of modules (drivers) that load during boot, add a line with "nvnet". Save the file and exit kwrite.
You are done!
Your sound and network drivers will be installed now, but you have to configure networking. For Debian, a very simple way to do it is using netcardconfig. You can down load the DEB file from here:
http://www.xs4all.nl/~groenewe/knoppix/Packages/
Install it using "dpkg -i netcardconfig*.deb" and run it with "netcardconfig". It requires the pump package for DHCP. It is also made for a Debian testing system so it may have dependecy problems on Debian stable, I'm not sure.
Hope that helps and good luck.