As some of you know, I recently got a PIC18F4XK20 development board. The black bar on the right side is actually a PICtail Header port, but it seems as if I can interface with each of the little connections individually, and it looks exactly like a mini breadboard. If I can in fact use it as a breadboard, I would like to try to connect one of my PS/2 keyboards to it. However, I have absolutely no idea how to interface using PS/2. I tried looking at the pinouts (here), but I am even more confused now than I was starting out. I'd like to know how to get the ASCII value of the character currently being pressed on the keyboard (and if I need to know how to do anything else to do this, I'd also like to know about these things).

PS/2 hardware and protocol interfaces.

Basically, four of the six pins are used: two for data, one for ground, and one for power. The protocol is a serial protocol, and follows a well-defined format in both directions. Also, PS/2 keyboards and mice use the same protocol; the only thing that's different is the messages sent. Also what Tari said.