In recent years, many PC peripherals have adopted USB or Bluetooth to connect to PCs, but until USB became mainstream in the mid-2000s, connections via PS/2 connectors were common. Raymond Chen, a ...
Nearly every barcode scanner I've run across is effectively a keyboard. I'd give it a try with one of the commonly available ones; worst case you can always return it.
[REVENGE] pointed out a couple cool little project posts from the geekhack fourms converting vintage keyboards to USB with a Teensy. They both have VUSB support, so any avr micro controller that meets ...