Tower hobbies listing of radios
http://www.towerhobbies.com/listings/cat-cat-j.html
most r/c vendors also refer to "channels" when you buy your radio this is what lets you select the frequency at which it will operate this link specifies the various channels
http://www.towerhobbies.com/help/frequencies.html
for our uses we need surface channels (61-90)
as for brand I recommend Futaba also the tower hobbies brand of radios seems to be constructed by futaba and from what i have seen are good quality. Ni cad batteries are included with most 4 channel systems (good thing I never seem to have enough AA batteries to operate the one radio I have that doesn't use them) or you can use normal AA batteries.
However you may need to make or buy some adapter cables to connect your receiver to the edu-rc I'm not sure of the brand of the cables used by IFI but i think they may be jr style? (its been a few years since Ive bought a radio)
EDIT:
according to IFI page 6
http://www.innovationfirst.com/FIRST...10-15-2003.pdf
The voltage fromt he full-size FIRST Robot Controller PWM OUTPUTS is too high and will damage the EDU RC, voiding your warranty