Ask HN: Charging for an application

I've got an application that is part iPhone app (perhaps other smart phones in the future) and part web site. Believing in the start charging immediately philosophy, I want to do just that.

What I can figure out is how. I've written a blog post at http://softwaremaven.innerbrane.com/2009/05/how-to-charge-for-application.html that goes into some details, but I'd love feedback on the best way to move forward.

If I left something out, please point out my ignorance.