VirtualWireInterface Arduino to low cost RF wireless modules to provide high performance transmitters, receivers and transceivers for data. Circuit diagrams and documentation here, download here.
I cant use i2c or serial
So my thought now was to use the PWM out from one Arduino to analog in on the other.
and for discussion sake here is the other stuff im doing..not directly on the arduino its a chipkit32 and faster so I know as far as i can see that firmata wont work on it but simple serial stuff should..and im testing the serial for arduino anyway