VNC

Short for Virtual Network Computing, VNC was developed at AT&T and enables users to control another computer easily and remotely. What makes VNC a great utility is that it enables users to control remotely numerous computers even if they are not running the same platform. For example, a user may be using Microsoft Windows and remotely connect to other Windows computers, Linux computers, or even Mac computers. Even better is that this utility can be used for free.

Also see: Networking definitions, Remote desktop, TeamViewer