With these tools in your arsenal you can glue any two systems together. The edge of one display rolls to the one next to it, and you only use one keyboard and mouse. The nice thing with this setup is that, unlike two monitors on one system, the two systems actually run independently (CPU, disk) and can be a mixture of Windows, OS X and Unix.
The first priority was to be able to use my iBook sitting across the room from my Wintel box, so I grabbed a VNC server for OS X and the relevant client for windows. Nice enough, but the redraws even on a LAN suck. So I moved the iBook over next to the 21" LCD, and avoided redraw issues by using them separately. But I still can't get used to the trackpad and moving from one to the other was a physical context switch.
Knowing about an old X windows tool called x2x, I managed to find win2vnc, which is a neat Windows VNC client that makes the edge of my desktop "attach" to the VNC server on the iBook. There are no redraws, since the iBook draws the video locally and I can use my same keyboard and mouse. Smiles all around!
The Mac equivlant of win2vnc is called osx2x, which is described as:
osx2x is a small Mac OS X application that lets you control other machines running either an X11 server or a VNC server using your mac's mouse and keyboard. So if you happen to have a mac and either an X Windows machine or a amchine running VNC on your desk you only need to use a single keyboard and mouse!I haven't actually used osx2x, only win2vnc, but provide the above since most readers are likley Mac-centric. I also haven't tried this with the firmware hack on the iBook (support for higher rez external monitor and the built-in LCD at the same time) to give three displays from two computers but it should work.
Mac OS X Hints
http://hints.macworld.com/article.php?story=20040324051216861