Question: I'm trying to run an app from a remote X session (Ubuntu, 9.04) on a handheld device powered by Windows Mobile. I want to do this by running an X-server of some description on the mobile device and using SSH/PocketPuTTY or similar for a tunnel, as you'd do it on a standard PC/Mac.

Can anyone point me in the direction of some X servers for Windows Mobile, if they exist?

Answer: 
I believe that [MI/X](http://www.microimages.com/mix/) will run on Windows Mobile.
I find your question is a little ambiguous. Do you want to run an app on windows CE and have the output on Ubuntu, or the other way around? In either case, I've never been able to find an X server for windows CE (I've wanted to do something very similar in the past). X servers tend to be rather resource hungry beasts. 

The only alternative I can think of is to use something like VNC to achieve a similar result.