Success! (I think...)
I got the IR circuit bread-boarded. I used the program from HERE
His circuit uses an 100 ohm resistor, I found my IR Led needed a 38 ohm resistor (I used a 47 ohm).
To test the IR circuits I downloaded his program to my arduino and experimented until it worked.
The IR Led needs to be quite close to the TV, but it seems to work. Maybe I should put a transistor in there to boost the signal...
Now I have to figure out how to diagram the circuit...
