" VNC (Virtual Network Computing) is a gift from AT&T
Laboratories Cambridge for users who want free, low-bandwidth,
cross-platform remote control of their systems. VNC runs on all
Unix variants, Windows, and Mac.
"But wait, you say, what about the X protocol itself? X is nice,
it has been called a network protocol that draws pictures. However
it is bandwidth-hungry, and works best on Unix machines. It's less
helpful for getting to the majority of the applications running on
your Windows or Mac machines.
"What about SSH? SSH (secure shell) is wonderful, in my opinion
the best choice for secure remote access. (technically, it's not a
shell, but a protocol). There are commercial and free versions, and
versions for all platforms. It's more complex to set up and use
than VNC, and has more capabilities, though VNC can do one thing
that SSH cannot. We'll get to that presently..."