Hamachi is a centrally-managed zero-configuration virtual private network (VPN) freeware application capable of establishing direct links between computers that are behind NAT firewalls without requiring reconfiguration (in most cases); in other words, it establishes a connection over the Internet that very closely emulates the connection that would exist if the computers were connected over a local area network. Currently available as a production version for Microsoft Windows and, as beta, for Mac OS X and Linux.
So you can play games or share files with your friend over internet with static ips, like a local area network.Here is the final version of Hamachi Portable. :-)
