Hamachi : Stay Connected
Hamachi is a zero-configuration virtual private networking (VPN) application.In other words Hamachi is a program that allows you to arrange multiple computers into their own secure network just as if they were connected by a physical network cable.
Reminds me of the old Nullsoft WASTE thing. So this is for creating a VPN ‘twixt friends for sharing files or running little private gaming networks. Neat stuff. Slick GUI, runs as a Windows service. I haven’t tried it out yet but I’m very intrigued.

I haven’t used it, but I’ve heard good stuff from everyone who has (like friends at work, etc)
Hamachi is awesome. I’ve used it for a while now and it’s just one of those programs that “just works”, even behind routers and firewalls and such. Hit it up!