Rocket Commander in XNA
Benjamin Nitschke released Rocket Commander for XNA with full source code. The game requires Direct X Dec2006 along with the XNA Framework. On an xbox 360, it runs about 60 frames per second with full screen antialiasing. Benjamin goes on to explain the pro's and con's of porting to XNA also.
If you're interested in the XNA Dream Build Play contest, you may want to check out how Benjamin did Rocket Commander too.