HTC just added the ability to change your gameID ingame.
From the News page:
"You may now change your game ID from within the game! In order to do so, you must be online and connected to any of our online arenas to proceed. You may also check to see if a game ID is available by using the radio dot command ".test id gameid", where "gameid" is the ID you wish to check for availability.
1) From the tower, bring up the clip board and select the "O'Club" option.
2) Then select the "Change Game ID" option. Type in the game ID you want to change to. If the game ID is available, a warning box will pop up notifying you of the ramifications of changing your game ID.
3) If the game is already taken, a warning box indicating as such, will pop up.
Please note, the following conditions.
If you are muted or have lost your chat/voice priveleges, then you will not be able to change your game ID.
You can only change your game ID once every thirty days."
