Have you ever wanted to setup a LAN between two computers and backed out because of the wiring costs? Then these types of software are the solution. VPN software allows you to use the Internet to create a virtual LAN between the computers. Although the speed of this type of LAN will not be able to match the real LAN's one, you can use it for doing some pretty neat stuffs across the Internet. It is recommended that you use a broadband or quicker internet connection type.
If you want to learn more about VPN, check out Wikipedia's article on it or chek out this website to get more information and tools.
Hamachi - Free Virtual Private Network (VPN) Software
This software allows you to create a secure VPN over the Internet. You can then establish communication between the computers and share data. Hamachi works on both Windows and Linux and MACOSX.
OpenVPN - Free Virtual Private Network (VPN) Software
One of the best VPN software availble on the Internet. It works on a wide variety of platforms and supports SSL (Secure Socket Layer) connections. The platforms supported are Windows (2000, XP, 2003, Vista), Linux, NetBSD, FreeBSD, OpenBSD, Solaris and MAC OS X.
UltraVPN - Free Virtual Private Network (VPN) Software
This software, derived from OpenVPN, acts as a client and server Virtual Private Network solution. This means that a terminal's connection to the main computer is private (encrypted) and nobody can access it.
WallCooler - Free Virtual Private Network (VPN) Software
This is another VPN software which allows you to create a virtual LAN between computers and this ones also works on Windows.