Amazon.com has a Trendware TK-400K - KVM Desktop Switch Kit - 4 Ports for $29.89 after $10 rebate with Free Shipping.

• Use one keyboard, monitor, and mouse to control four computers
• PS/2 and USB keyboard/mouse emulations
• 4-Port KVM switch in palm size design
• Hot-Plug feature adds PCs or remove connected PCs for maintenance without powering down
• No software required, easy PC selection via Push Button or Hot-Keys

Click Here for the DEAL