http://www.hervalfreire.com/blog/?p=17
Controlling two computers with one keyboard and mouse - the software way
Synergy is an open source (read: FREE) tool that allows you to control several computers with one single set of keyboard and mouse. Another good news is that Synergy supports Windows, MacOS and Unixes (although with a few bugs on the latter two, according to their site).
[url]
http://synergy2.sourceforge.net/[/url]
Linux
http://www-128.ibm.com/developerworks/cn/opensource/os-mltihed/index.html
http://www.maxivista.com/
windows
Multi Monitor Software Solution
MaxiVista turns any spare PC into a second monitor for your main computer. No extra hardware required. You can seamlessly extend program windows across multiple screens like it would be a single big monitor. Increase your productivity by using multiple monitors (more info)
http://www-128.ibm.com/developerworks/cn/opensource/os-mltihed/index.html