Try the obvious - Microsoft! They should have a sample driver for the NE2000 chip, the RTL8139 is based on this (methinks!). Failing that, look at the linux drivers and extract the info you require - your level of windows integration only needs to be minimal - you can define your own packet read/write calls in a DLL rather than have a full windows driver which is what you need if you want windows to communicate via it.

This is not quite the right forum to ask such questions!