I just did this on Gutsy, and I thought that it might be worth sharing as a simple way to set up a persistent VNC server. If you dont know what VNC is, its similiar to Remote Desktop for wind0ze. This is accessible using regular vnc viewers, and through java-enabled browsers. That's right, you work on your computer through a browser.
1) Install packages
sudo aptitude install x11vnc vnc-java
2) Set up password to allow clients to view
3) Open up ports 5800 and 5900 on your firewall
4) Run this command: x11vnc -forever -usepw -httpdir /usr/share/vnc-java/ -httpport 5800
And an optional step 5:
5) Add the command from 4) to your sessions, so that it starts at each login
If you want to test it out on a browser, type this in the URL field:
Of course, replace the 25.etc. w/ your external IP address.
Addendums to this are welcome, such as how to make it more secure. I just thought it'd be nice to have a quick and dirty tutorial for getting this set up easily.