Sharing video+kb+mouse over TCP/IP

• VNC
• Remote Desktop (windows only)

Sharing kb+mouse over TCP/IP (each machine has own physical display)

• Synergy (seriously good shit)
  (auf AHK (auf Deutsch))
• x2x / x2vnc / win2vnc

Sharing kb+mouse over USB/PS2 (each machine has own physical display)

• use a normal KVM, and just don't hook up the video to anything (works great, actually)
• use a USB-switcher that supports keyboard-switching (basically a KVM sans video)
  • several listed here
• USB-over-TCP (injected at the hardware level, so works in BIOS and regardless of what OS is used)
  • AnywhereUSB
  • MultiSwitch
  • USB to Ethernet Connector
• USB-over-TCP (injected via hacked device drivers, so software only (eg. free), but doesn't work in BIOS)
  • usbip.sourceforge.net (pre-alpha)
  • USB Over Network
  • USB Redirector
• PC-based KVM, implemented using commodity hardware, and fancy hardware? Is this possible?
  • To some extent, no. PC USB cards are almost exclusively host controllers. What is needed to "send" a USB packet to another computer is a USB card that allows it to act as a perhipheral device. (in USB, data-flow is strongly directional... the master/slave relationship is a fundamental part of communicating. (though USB OnTheGo tweaks this slightly) We need a PC card that can act as slave (eg. a card that has type B connectors). When have you ever seen the ability for one computer to plug into another, and for the first to magically appear as a mass-storage device? Or a keyboard? Certainly it's possible, but not common)

For completeness...