When I get a little more time on my end, I can elaborate on this a little more thoroughly, and there's surly someone who can answer better than me (not having actually competed in the IFI days), but I'll give it my best shot.
An overview of the control system can be found
here. Basically, there are two parts, the Operator Interface (OI) and Robot Controller (RC). These are the predecessors to the cRIO and driverstation, respectively. Everything plugs into the RC (it has rows of pins for all I/O types you'd need). As for programming this, start by going
here. Eventually, you'll need Microchip MPLAB 7.2 and the C18 compiler. You can find both of these online somewhere (although I think only a trial for the compiler), but things would be made much easier if you could find your install discs from a few years ago.
That's the best I can do in the short amount of time I have, but I'll get back to you later in the day with more.