"The cost of application is added to the customer's monthly bill."
here we go...not a so good news
Some developers may actually like this model because it reduces the piracy of their applications. If they could sell a $4.99 version of their application, not have to worry about distribution, not have to worry about taking care of the billing, etc., it would be kind of nice.
Considering what customers are paying for their monthly AT&T bills, an occasional $4.99 bill thrown in for a nice, shiny new application for your iPhone probably won't be so bad.