This is all new and it seems like different foundries are all trying out different approaches. This has been my approach:
Technically, the specs I've seen for ipad app development recommend using .otf files. This isn't always the case, depends on the develop. Hinting-wise, it's a rotating screen with Apple rendering, so there's not much you can do anway. For OT features, I've had to build custom non-opentype, subset (to mac roman) versions.
Licensing-wise, it depends on the method the developer is using. For otf method, I've been approaching it similar to how I would for font encapsulation for software or video games. To keep things simple and fair, I try not think too hard about how the is going to distribute/sell the app. Those numbers are almost always complete guesses and it's not worth my time to try to parse their business model (sku/month x price + views/month x ad_rate) / the imaginary value the use of the fonts add. Instead I go with a flat rate with a discount for licensing multiple styles/weights.

"What determines the pricing?"

I think you do.

There's likely no real correlation to existing models so it's kind of a wild-west area for licensing.

I’m not asking from a type designers perspective (at least not yet), so I’m probably not the one to decide. I think the fact that the iPad/Pod/Phone is a closed system should have something to say. The fonts are not available in the same way they would be if they were embedded inside an application on a regular computer, although I guess that never stopped pirates.

@Jackson:
I take it OT fonts are only used in native apps? Or does Safari support OT? You can design applications as a website in HTML5/CSS/JS packed inside a custom shell that is really no more than a webkit browser.

I was talking specifically about developing native apps. For me, it all depends on how they are using the fonts. If it's a raw font or a web format, bundled into the app (in the library or package contents), and being redistributed (as opposed to downloaded and cached) I consider it encapsulating.

Is it possible to download a webfont to the cache in an app?

There are various ways to build the apps. I can't speak for native Objective-C apps, but (at least in theory) one could use @font-face when writing an app via HTML/CSS/JS that then gets compiled via xcode.

One can also build a web app based on HTML5 browser caching where you can tell the iOS (or, more precisely, I suppose, mobile Safari) what elements should be cached for local use on the device. I'm not sure if that can include font files or not.

Some info here:

http://www.thecssninja.com/javascript/how-to-create-offline-webapps-on-t...

Darrel, that is a very helpful article. Thanks a lot!

Since this is new terrain, I guess it's a good thing I got the discussion started.

I got in touch with the foundry in question for my project, but the price exceed the planned retail price ($5) by far. Even if we reduce the number of fonts to an absolute minimum (three) native embedding appears to be totally unfeasible.