I have had the best luck using the NVIDIA_nforce-1.0-0261.src.rpm, and using building the RPM. That way, you are sure to use the current source file, and build a kernel specific module. Here is the download page:
Once downloaded, login as root, and install:
rpm -ivh NVIDIA_nforce-1.0-0261.src.rpm
Next, go to /usr/src/redhat/SPECS
rpmbuild -ba (spec file name) - sorry I can't remember what it is..
This will build the RPM for installation (and I think it automatically installs it). The driver name is nvnet. Make sure this is in your /etc/modules.conf file for the appropriate ethernet card:
alias eth0 nvnet
Lastly, keep in mind that if you decide to upgrade to the 2.6 kernel (i.e. Core 2), this driver will no longer compile. Instead, the 2.6 kernel has the driver "forcedeth" included, which does the same thing.
Hope this helps!