Teamviewer

TeamViewer is a computer software package for remote control, desktop sharing, and file transfer between computers. The software operates with both Microsoft Windows and Mac OS X and functions even if the computers are protected by firewalls and NAT proxy. It is also possible to access a machine running Teamviewer with a web browser. While the main focus of the application is to facilitate desktop support and remote control of computers, collaboration and presentation features are included within the package.

http://www.teamviewer.com/nl/