Just 2 weeks ago I built the same setup; Asus P5W-DH Deluxe, Conroe E6600, Inno3D Geforce 7950GX2 and Corsair TWIN2X2048-6400 2GB RAM. It runs beautifully.
I've got pretty much the same set up as well, the Nvidia control panel reports it as being in dual gpu mode (91.31 driver). And I've been running Qukae 4 with max settings at 1920x1200 and it runs great. So I'd say yeah it is definitely running in dual gpu mode.
Yeah I run Tiger Woods 2006, Oblivion, TrackMania Nations, Ghost Recon Advanced Warfighter, DoD Source, CS Source all on max @ 1680*1050 without a hitch.
So I'll confirm what kalthak has said, yes it does work properly on this setup.
what would this motherboard say to a 2nd 7950? I ordered this motherboard but its on back order so I can still cancel it, but i'm not sure that there's a good SLi board out, guess I need to look into that.
You can't run SLI on that board. If you want SLI with the 7950 GTX I recommend that you wait for Asus to release a 590 chipset board for the LGA775. It should be on the market shortly and will be worth the wait. Remember, the 7950 GTX really needs 32 lanes of PCIe to run properly in SLI.