If any software has been adapted to successfully display the N900's screen and export mouse and keyboard control to another computer, it is a breakthrough.

Other than x11vnc server running on the N900 with some problems (screen blanking, keyboard kludges, etc.), there seems to have been no success with operating the N900 from another computer.

There are a number of threads which begin by telling you how it should be done, then run into a lower level problem and go no further, and leave it all hanging after you've spent an incredible amount of time reading about the topic.

My favorite is following the long, twisting trail for X forwarding over ssh
http://wiki.maemo.org/X_forwarding_over_ssh
which says to install a package on a web page, which web page turns out to be actually a bug report:
"Bug #2494 provides all the information you need to export N900 X clients to your Linux desktop display"
https://bugs.maemo.org/show_bug.cgi?id=2494