I don't get any kickbacks I swear.  Check out MaxiVista it is truly a great product a number of people here use everyday.  It is a simple client/server application that provides software based multi-monitor and KVM functionality.

...Really, I don't have an affiliation with them what so ever.  It is just a great product.  If you bring a laptop to work like I do, it is a necessity.  Instant KVM and Multimon without waiting for new hardware.  Enjoy and please pay for it if you use it, they've earned it!