Be sure you get the kind of KVM switch that allows you to use just one keyboard and mouse for both computers. You want the actual switch to be where you can get at it... not behind the monitor so get the extended cable with the switch on the end. AND check your connections on your monitor to see what you need on the KVM switch.
Nothing like having everything torn apart only to find out your cable won't connect to your monitor without more stuff to bridge it.
Iogear GCS22U USB KVM Switch With Cables And Remote 6
IO Gear KVM switchhttp://www.staples.com/IOGear+GCS22U/directory_IOGear+GCS22U?