UltraVNC is an easy to use, fast and free sotware that can display the screen of another computer (via internet or network) on your own screen. The program allows you to use your mouse and keyboard to control the other PC remotely. It means that you can work on a remote computer, as if you were sitting in front of it, right from your current location.
If you provide computer support, you can easy access your customer's computers from anywhere in the world and resolve helpdesk issues remotely ! Your customers don't have to pre-install software or execute complex procedures to get remote helpdesk support. UltraVNC allows you to remotely control a computer over any TCP/IP connection.
UltraVNC key features include FileTransfer, Video Driver, Encryption Plugins, MS Logon, high performances over all kinds of connections, Viewer Toolbar, JavaViewer with FileTransfer, autoscaling and serverside scaling, Multiple Monitors support, Repeater/proxy support, good Security and Text Chat.
UltraVNC also has powerfull addons like Repeater, SingleClick packager and Nat to Nat connector, that help you to easely handle the most complex connection situations.
UltraVNC runs under Windows™ operating systems (95, 98, Me, NT4, 2000, XP, 2003...), but its embedded JavaViewer allows you to connect (and make File Transfers) from a simple Web Browser on any Operating system supporting Java™ (Linux, Mac OS...) to an UltraVNC server.
What should I say more, well I have removed RealVNC and have installed UltraVNC. The number of options and features in this open source application is more then RealVNC. Another tight contender for the same would be TightVNC but thats another day :-)