Step 1: Install SOCKScap on your client machine.
SOCKScap is freeware and available from http://www.socks.nec.com
On the general settings configuration menu in SOCKScap (choose settings off the file menu) you should specify the following information, substituting the internal IP address of the machine you run SpoonProxy on for the 192.168.0.1 address listed below. Specify port 1080. Specify SOCKS5. And select the radio button for resolve all names remotely.
Step 2: Click the direct connections tab. You will need to add 6112 to Direct UDP Ports as show in the following screenshot.
Then run the program (Starcraft, Diablo, Warcraft, etc. socksified and you should be able to connect to the multiplayer games as if you were directly connected to the internet.
Note: You will only be able to connect one client machine at a time. (This is a limitation of the games themselves because technically you only have one external internet IP. Also you may not be able to join any games, only create a new game and invite others to join.)
Also, note that these instructions may not work with the demo version of Starcraft, etc.
For more information on these games please visit http://www.battle.net or the Blizzard Software homepage at http://www.blizzard.com.