The answer is Probably Yes. PCI ethernet cards are fairly safe to swap around, and since everyone shares just a handful of common ethernet IC's, you're likely to find that your Mac has the appropriate drivers built-in.
Then again we've all had our share of Not Yet's with OS X.
Ethernet cards are kind of a coin toss with a Mac. I've got a Real Tek card in my G4, which is the only 3rd party card with OS 9 drivers (that I know of.) OS X doesn't support it. Has anybody tried OS X with Netgear cards? Maybe I'll give it a whirl if I get bored.