Before you test with the RF modules, make sure that your system works when the
two microcontrollers are connected with a 1k ohm resistor.
Make sure that the two PIC microcontrollers share the same ground. (GND).

Code:
PIC #1                 PIC #2
             1k
TX Pin-----/\/\/\------RX pin

GND -------------------GND
Both microcontrollers must use inverted logic.