Drop by the irc chat channel when you have some time (see Chat button at top).
I think the most important thing, based on experience i've had working with others, is to figure out what would be a reasonable project/goal that could be achieved and implemented in the time you have.
One of my biggest problems is getting carried away with ideas and then eventually they grow too big and you get un-motivated.
So some planning ahead of time will go along way -- and figure out a good small game to make that won't drive you to the bring of insanity and exhaustion. (you can save the exhaustion and insanity for version 2 of your game).
Why not start a new thread in the Developer's Corner section of the forum: http://www.donationc...index.php?board=75.0
Title it something informative like "Requesting help with ideas on making a Tower Defense Game"
And tell everyone a little about your background, what language you might want to program it in, etc.