I'm betting Apple puts up an iPhone section in iTs (i.e. Music section, Movies section, etc.). And this is were you'll be able to purchase/get ringtones, apps, widgets, games etc.
I also think this is what Apple means when it says that it wants to be in control of the release of new third party applications for iPhone. Apple wants you to buy them and mange them from iTunes.
Remember it's still early were at least a month away from WWDC and I expect the rest about iPhone to be released at the keynote.
"Welcome to WWDC 2007. I don't want to spend alot of time on the iPhone because were here for Mac, but I have to tell you this because it's coming out tomorrow..." -Steve Jobs WWDC07
Oh what I would do if he'd say that.
PS: Splinemodel, how do you like the UpStage. I've read some great reviews. I wouldn't buy it because Sprint isn't to great around here, but I have high hopes for it. It definately looks cool.