I just thought I would bring up an idea I had that I don't think has been mentioned before. When I get my 30 gig Rio installed, I plan to stash a Linksys WAP11 somewhere in the dash out of site. My plan is to use one of the auxillary controls on my Viper brand alarm to switch a relay that will supply 12 volts to the ignition sense wire of the Rio as well as to the Linksys through a 5 volt regulator circuit (the Linksys runs on 5 volts). This way I don't have to concern myself with setting the shutdown delay to some really long number when I want to upload songs to the Rio in my car. When I'm done uploading I'll simply hit the button on the keychain remote again and both the Rio and the Linkys will power down.

My only concern is that the alarm system cannot be configured for toggling between on and off (maintaining signal to a relay until told to do otherwise).

Other than that it should work. If my concerns are true, Velleman at www.velleman.be makes a receiver and transmitter kit that would do exactly what I want, but would require 2 keychain remotes (the alarm one and their transmitter one).