I have the Samsung SyncMaster 940BF.
What is this KVM switch thing?
Well they already answeredthe second part, so that's good.
But based on the specs for your monitor youshoudl be able to plug one PC into the VGA connector, and the other into the DVI connector (as long as you havea DVI out on one of the PCs) and then voila without added cost 2 PCs on the one monitor, like was mentioned by dhvd79a.
However if both are VGA output only, then you will need a KVM, if both are DVI (as long as not both the old DVI-D like on the R8500) then you can use a DVI->VGA adapter and plug them both in.
Anywhoo, you shold be able to figure it out from here as to which best suits your needs, I'm off to watch the game.