Extramon lets you use a second computer as a second monitor, giving you a dual-monitor computer. In fact, both of your computers become dual-monitor computers. And you can operate them both from a single keyboard and mouse. No hardware or cabling needed. All you need is two networked computers sitting side-by-side.
Extramon sends video across the network and displays it on the other computer's monitor. Windows thinks that each of your computers has two monitors. Extramon has an on-screen switch that allows you to choose which computer you're looking at. You can turn off dual-monitor mode at any time and just operate each computer individually from a single keyboard and mouse.
Nobody every complained about having too much screen space. If you have two computers available (such as a laptop and a desktop), it makes sense to use them both.
Having dual monitors lets you keep your email open on one monitor while you work on the other.
You'll spend less time switching back and forth between applications.
Notes for Windows 7 and Vista users:
The Extramon video driver cannot be installed alongside a WDDM video driver (i.e., on a computer with the Aero user interface, which gives you the fancy graphical effects on Windows 7 and Vista). See this page for more information.
Also, the Extramon video driver cannot be installed on a computer running Windows 7 or Vista x64 Edition without restarting the computer and using the F8 option to permit unsigned drivers. Without using the F8 option, you cannot extend the desktop of a Windows 7 or Vista x64 computer (although you can still extend the desktop of an adjoining computer).
Requirements: Windows 7 or earlier (back to Windows 2000) on each computer. (The download includes true 64-bit software for Windows x64 Editions.)
Extramon - 64bit software