I know Hamachi has already been requested and there were issues about the source code not being available.
Well I found this with some searching. I haven't used it yet, but it seems to do pretty much the same thing as Hamachi. And it's an open-source program.
This would be useful for my non-gaming needs at my not-school when my non-friends and I don't get bored.
The website is here: http://wippien.com/
Anyone think they could make this runnable off of a flash drive?