Connecting A Meade ETX-70AT Telescope To A PC?

ronys asks: "I've just bought my son (yeah, sure) a Meade ETX-70AT telescope. It's a pretty cool toy, with an RS-232C port and an optional ($$$) cable and software that connects it to a PC. Since there's nice 3rd party software that supports telescope control, I was wondering if anyone has already hacked the pinout of the serial cable?"