If you have updated your Mac recently or have an only one just gathering dust, an application called ScreenRecycler might be able to help you put it to some use after all.
The ScreenRecycler will convert your older Mac system into a usable second monitor increasing your desktop space. Watch a video of the ScreenRecycler application in action after the jump.
If you own two computers with separate screens you can use ScreenRecycler. Even your laptop can be used as a second screen for your main machine. ScreenRecycler is available to purchase for $30 from the ScreenRecycler website.