http://www.cold-war-crisis.de/wbboard/portal.php Probably the best total conversion ever made for C&C Generals Zero Hour and uses the engine to the maximum potential. The campaign is reminiscent of Operation Flashpoint and has a good solid gameplay to it and sometimes I wish it was a stand-alone game. I'm not sure if they are still working on the mod or porting to a later edition of C&C but so far the game only has the two usual sides; USA & USSR, though they were working on the European Alliance.
C&C Generals doesn't get enough love. It was a pretty damn good game. There's also a mod for Zero Hour called "Shockwave" that's pretty awesome.