CrossLoop is a tool for distance that allows to control a remote computer.
Connecting to remote servers using SSH, Telnet or Rlogin is much easier with PuTTY.
Viewing and even controlling one remote computer from another desktop computer is possible with RealVNC which also offer the possibility to do this with computer with different platforms.
Troubleshooting a shutdown, making a presentation, working with a team, managing a server, from remote computer can be easily and nicely done with TeamViewer.
TightVNC allows to remotely control a computer via Internet making it very easy to take care of a computer maintenance.
Troubleshooting becomes very easy with UltraVNC as it allows to remotely control a computer from another on using the Internet connection.