Eddie,

most experienced instructors have a trainer cable ( and often a spare TX ) for all of the brands they normally instruct with for buddy box work which they will share with you. The club also has some training equipment at the field which instructors can access for you.

I think there was a recent proposal on one of these forums that the club training equipment was to be renewed soon.

Some equipment can intermix for buddy box work.

Hitec/Futaba: http://www.rcgroups.com/forums/showthread.php?t=63736

JR/Spektrum: http://www.duanesplanes.com.au/product.php?productid=285
( JR's R/C trainer cord links any two JR or Spektrum transmitters to create a master and slave transmitter set for flight training. )

This is very simple electronically as the trainer switch just decides which stick pulses are sent to the master TX ( a PPM signal at standard logic levels )

...and for the techo lunnies out there here is some appetite wetter for hacking a Futaba/Assan marriage http://www.youtube.com/watch?v=TGZ8sepQ_94