VNC - Virtual Network Computing from AT&T Laboratories Cambridge
"VNC stands for Virtual Network Computing. It is, in essence, a remote display system which allows you to view a computing 'desktop' environment not only on the machine where it is running, but from anywhere on the Internet and from a wide variety of machine architectures."

VNC is a cross-platform remote access application compatible with UNIX, Linux and Windows 95/98/NT/2000/XP. It is simple to install and configure. Best of all, its free.