Thanks, that's a good point, I completely forgot about the reset pin! I've just been looking at your Tiny Tuner stuff here:
http://arduino.cc/forum/index.php/topic,8553.0.html
and I just want to get a few things straight before I potentially damage a chip...
I upload the sketch 'Interactive_to_Serial' to the ATTiny.
I connect PB3 (which is transmitting) to the serial receiver and PB4 (which is receiving) to the serial transmitter.
The Receive/Transmitter presumably can just be the TX/RX pins on an Arduino Uno for example?
Then, set up the Uno to transmit 'x' at baud rate 9600 over TX and reset the ATTiny85.
Forgive me if anything here seems wrong, I'm new to this whole thing 