I have four computers at the moment sharing one keyboard, video, and mouse using a KVM switch ("KVM"= Keyboard Video Mouse). As my machine count has grown over the years, I have acquired new switches to accommodate additional machines and new port requirements (PS2 vs USB).
My current KVM switch is an IOGEAR GCS1724 4-port box-type. Of the five KVM switches I have used since 2003, my current IOGEAR GCS1724 is by far the one I would recommend (depending on machine requirements)....