I control it using Indigo which is a home automation tool that allows you to fire applescripts from a browser interface which obviously I can access through the Pronto (no doubt there are other ways but this fits with my overall solution). There is already a pronto module that allows you to talk to Indigo (scan the Indigo forums). If you have X10 or many other home automation products, Indigo will control them allowing easy automation off the pronto also......

If you look in the Airfoil support section they already have examples of the applescript code required to select the audio source to hijack, turn speakers on and off and set their volume. Even I could do it so it was not that tough! Even used it to hijack Spotify the other day and play it out through all the Airport Expresses in my house simultaneously! Got a big ooooo from the assembled punters.

Now just thinking about how I can control spotify through Applescript or get Tenchi to write a ProntoSpotify module (he is giving some lame excuse about Spotify having not made it to Aus yet). Come on Tenchi! Just because you can't beat us at cricket anymore don't be sore!