General#

• Synergy: control multiple machines with on set of mouse/keyboard
• X11: remote display/control
• VNC: remote display/control with lower abstraction level but high portability
• ssh: text mode display/control. Can forward X11 too.

Windows-related#

Windows does not know about having multiple displays like X but there are solutions that create virtual displays that can be shared/exported:

• http://www.zoneos.com/zonescreen.htm
• Maxivista (not free) Windows has remote desktop but a special license is required to allow multiple users simulaneously.