nvidia nforce 1.0-261 nvnet for kernel 2.5

from various hardware source the NVNET hardware is probably this:

MCP integrated NVIDIA^R MAC + Realtek^R 8201BL PHY

The specs on asus and epox refer to using the nvnet on the some fo their boards, in the detailed specs you get the above detail

Hope it helps
I could be persuaded to do some testing if required