For instance, my regular mythtv back and front ends are Ubuntu lucid LTS (10.04); but I also have a macbook pro (running mac osx), and a Lenovo U400 running Ubuntu precise.
Here's how I setup xbmc as my mythtv frontenv.
My myth backend is 192.168.1.100
Install xbmc. Refer http://xbmc.org/download/ on howto, for your platform.
Install MythBox addon. Go to Videos -> Add-ons -> Get More.. and select and install MythBox.
Go into MythBox to where you can define the MySQL details. Here's how I've configured mine:
Spawn xbmc. Before we do that, lets route 6543 traffic to the myth backend server.
(Note: you can use socat easier than ssh, there is an example elsewhere in this blog to use socat)
$ /usr/X11/bin/xterm -title "Close_me_after_myth" -e "ssh -c blowfish -L 6543:localhost:6543 192.168.1.100 cat - "
$ /usr/bin/xterm -title "Close_me_after_myth" -e "ssh -c blowfish -L 6543:localhost:6543 192.168.1.100 cat - " &
Start MythBox, enjoy