Where does it say it supports Sirius XM, I don't see that anywhere in that linked web page description.
Don't say that too loud, they may decide to turn Coffee House into the all Indigo Girls channel or something. It's clear that apps like this are for current subscribers only, since there won't be any packages offered for new subscribers to try it through their iPhone or iPod Touch. If they were smart they would, but they've already proven otherwise several times over.
Well I think you are a bit ahead of the game on them having a select few channels for folks to try out on the iPhone/iPod considering Sirius XM technically doesn't have an application yet.
I think once they get an application, we may seem them move to open a few rotating stations for folks to try out the free Sirius XM application online. Now they may do this at certain times like cable does where they give sneak previews, but clearly the application is more about enhancing the experiences of those subscribers that already have the service.
This application has done that for me, which I was on the verge of possibly canceling. Now that I have this method (no reception, docks, antennas to deal with) to listen which sounds decent I'll keep the service.
If Sirius XM would get their SIR service pricing at a decent price point, I think many would subscribe once they get a decent application released. Also lets not forget they do have the trial online service which would allow those who download the free app to try it for 3 days and they would get everything. I think that time should be more like 7 days, but whatever!