This software is developed by NoMachine and can be found
http://www.nomachine.com/
this company earns money by giving support for this software. It can be installed on Linux and Solaris. There is no server for Windows because the use of RDP server is suggested.
Install is easy (tested on Ubuntu 7.04).
http://www.nomachine.com/download.php]
http://michigantelephone.mi.org/blog/2006/09/how-to-install-nx-server-and-client.html
This is my source, you can find all needed there. Only thing I had to do (to allow log in to Gnome for Ubuntu default non root user) was
Remove gdm file from /etc/init.d/ and reboot
This will stop Gnome from running by default when you start server. So you will be able to start it remote with NX software. When working on console and want to have Gnome running, just run
startx
That is all, enjoy