TeamViewer, the famous remote desktop tool, has released a Linux version. Although Teamviewer for Linux is still at its beta stage, it was quite stable in my tests.
The Teamviewer Linux version is not as complete as the Windows one, the VPN feature is not (yet) included.
Download Teamviewer for Linux
Current release (5.0.8252) is available as deb, rpm and tarball packages.
Download it from here. (Only full version, no portable Teamviewer “quicksupport” module yet)
PS: TeamViewer is available for Mac and iPhone too.