x2vnc is a very neat little tool that gives you dual screen between two computers running different operating systems. So for instance I have a Gentoo machine as my main box at work, with the obligatory Windows machine next to it with it's own monitor. Running x2vnc on my Gentoo box I can just move the mouse cursor to the edge of the screen and hey presto it apears on the windows desktop. And the best thing is that the clipboard works between the two machines, so no more pasting stuff into temporary text files etc. Very nice. Give it a go, it's a bit spooky at first :)