A friend of mine said he figured out the XM hack.
Basically you have to sign up for XM. THey turn on your radio id,
you get the service. He said he let it run for 3 months or so, then cancelled. He said for the next 3-4 months of course his radio unit didnt work as they were transmitting the "kill" signal.
But he (having been a satellite haxor) hoped that XM couldnt afford bandwidth wise to transmit this "kill" signal from thereout for ever... he waited patiently, and a few months later they stopped transmitting the kill signal, and his unit started receiving the exact servic