I do support for pdas and get asked daily by somebody who's not tech-savvy enough to "find the good stuff" (however that might be) for somewhere to go to get new apps/ringtones/etc, for their phones. With the release of the iPhone tomorrow, having an official place to suck these types of people into, and likely being backed by every service provider that's selling the iPhone, tons of folks are going to blindly stumble into the Apps Store and spend because it's easy, and because it's there. Cost is less of an issue if you're led to believe that you're in the best (or the only) place to get something.