I have been enjoying having a second monitor on my desk at work. Unfortunately, it is a PC. But it would be nice to have a second monitor here at home. Many Mac users have a hard time throwing out an old Mac. Wouldn’t it be great if you could use that old iMac or eMac as a second screen?
That is basically what ScreenRecycler does via an Ethernet connection.
It is a $30 piece of software that allows you to use a second computer, even a PC as a second monitor.
See more information here.
Video of the process in action here.
