I often find myself with two computers on my desk and struggle to make the mouse pointer jump across to the other screen which never actualy works as they are different computers.
Enter Synergy It is a neat little app that allows you to attach that other computer as another screen of the one you are using!
Just set up the machine you use the most as the server and then run the client on the other machine. With a little config you specify which computer is on the right or left of what and away you go!
The only hard thing to remember is that the windows key and the apple keys are do different things ( still need to get my head around apple+c and control+c are both paste!)