there is a program called synergy - install it on both laptop/desktop.
You move your mouse to one side of the screen, the mouse/keyboard input is switched to the other computer.
I used to control my desktop from my laptop with it.
of course, your computers need to be networked together for it to work properly.
it is free -
http://synergy2.sourceforge.net/
More expensive, a Keyboard Video Mouse switch (or if available a Kyboard Mouse switch) - I have a KVM for controlling my desktop computers with one mouse/keyboard/monitor... I can press scroll lock twice, then a numbers 1-4 and jump to an other computer. Would also require getting additional cables to hook the switch to the computers (some do come with them already).
I would try synergy, it is really nice, I'm going to get it re-installed again.