Finding NIC firmware version
Well this is not native to 2008 that I know of. I would look in the command line utilities provided by the NIC vendors. You will need to have their management software installed to use them.
- For Broadcom NIC's I would try the "BACScli" command
- For Intel NIC's I would try the "prosetcl" command
More details on the intel command line tools can be found http://www.intel.com/support/network/sb/CS-029966.htm
These commands might be able to pull the firmware info as their GUI counterparts can display this information. If the commands will pull the data you need, you should be able to use them in a powershell script. And use WinRM or PS (sysinternals) commands to use them remotely if needed.