Mango Lassi is a GNOME program that lets you painlessly share keyboard & mouse (& clipboard too!) between computers. It's not packaged for Ubuntu yet so you have to build it from sources.
Big fat warning: Mango Lassi has no authentication and does no encryption, so use it with extreme care. Don't type any passwords over your unsecured WiFi network!
Here's how to get it working on Ubuntu Hardy:
$ sudo apt-get install git-core curl build-essential intltool \ automake-1.9 libdbus-glib-1-dev libgtk2.0-dev libxtst-dev \ libavahi-glib-dev libavahi-client-dev libavahi-ui-dev \ libnotify-dev libglade2-dev $ git clone http://git.0pointer.de/repos/mango-lassi.git/ $ cd mango-lassi $ ./bootstrap.sh
Press Enter once at the prompt.
$ make $ sudo make install
Now you can run it with
$ mango-lassi
When you're tired of it, go back to the source tree and type $ sudo make uninstall
If it only used an SSH tunnel for encryption & authentication, it would be perfect.
Porting it to Maemo would be an interesting project. Imagine copying and pasting URLs from your laptop browser to your N8x0 tablet browser. Is Avahi available for Maemo?