virtualbox.org

I want to setup VirtualBox on my work Computer which just used by myself. In this case, i need buy license? Where can i find some information about license?

The license is free for personal use, regardless of who owns the PC you put it on, and even if you personally use it for work related stuff.

License Terms: http://www.virtualbox.org/wiki/VirtualBox_PUEL
License FAQ: http://www.virtualbox.org/wiki/Licensing_FAQ

For VirtualBox 4.0, License if GPLv2