I run opensolaris on my new asus board. Had some difficulty with the Gigabit driver not being recognized but used the latest driver from the website mentioned by the device driver utility (http://homepage2.nifty.com/mrym3/taiyodo/eng/)
I first tried to set this MCP78S (Geforce 8200 Ethernet) as a nge0 device but had trouble with the reverse bug with the MAC address.
I then decided to set it up as nfo0 with the nfo-2.6.3.tar.gz.
Installation following the readme provided with the tar file went OK and revealed itself as pci10de,760.