Yes, but it's not the same strict async-type communication that most people associate with RS232C type communication. That is, the clock rate can vary from bit-to-bit, since it's the keyboard that provides the clock and data. In the PC, this is received by a 74LS322 9-bit shift register; when the start bit is clocked into the 9th bit, a keyboard interrupt is issued, the register is read and reset and the process starts over. You can clock bits into the '322 at any rate you desire, as long as it isn't too fast.
That's what allows me to get away with a cheap 8-pin PIC for implementation--and why I said it has nothing to do with baud rates. Don't mistake a serial bus protocol with async comms.
At any rate, if you want to fool with it, the code's been included somewhere in this thread (I forget where I posted it), the relevant routine is SendXTBit. The code's basically a bit-banger with software timing loops.