Connect to a Specific Network Port
If your Windows-based computer is configured to accept Remote Desktop connections on a network port other than the default port (3389), you can now specify the network port when you connect. To connect to a specific network port, type the computer name or IP address of the computer you want to connect to, type a colon (, and then type the network port number. For example, if the computer name is MyPC with an IP address of 192.168.255.255, and the network port number is 1234, you would enter MyPC:1234 or 192.168.255.255:1234 .

http://www.versiontracker.com/dyn/moreinfo/macosx/15544

Thomas