Remote desktop to Mac from various platforms (Windows, Ubuntu)
On the Mac: Go to System Preferences -> Sharing and enable "Screen Sharing".
On Ubuntu: Using any suitable VNC client (xtightvncviewer appears to be the most compatible), enter the IP address or host name or your Mac Mini and then connect. You should now see your Mac's desktop.
For added security, click on the "Computer Settings..." button in "Screen Sharing" to enable and set an additional VNC password if required.
I tried lots of things but this was the only thing that actually worked for me:
There are two tricks to using VNC from a non Mac to connect to a Mac running OS X Lion.
Turn on the VNC server by enabling System Preferences -> Sharing -> Screen Sharing. Even though it provides little security, a VNC password must be set so that OS X will present an authentication scheme that makes sense to a standard VNC client. Enable “VNC viewers may control screen with password“
After connecting, you will see a grey linen-backgrounded desktop with nothing in it. Type your user name and password. After logging in, your desktop contents will display!
Personally I think the best solution is not bitmap-based.
NoMachine (and other groups like FreeNX) offer something called NX. It is an X windows interface that provides for bitmap caching and compresses the line drawing commands that are sent to the graphical device. NX can be very fast over low speed connections because it does not send differences between screens as does the VNC protocol. Over high speed connections the quality and performance is excellent. It's at least as good, or better, than Remote Desktop on Windows.
NoMachine offers a free version of their server and client. They support Windows, Linux, Apple Mac and are now working on Android and iOS. You can download their free products or try their commercial products from this page:
https://www.nomachine.com/download
The FreeNX group also provides an NX server and clients but I'm not aware of any support for Apple Mac systems. Of course it's a good idea to keep up with their progress which you can do here:
http://freenx.berlios.de/