title: iPhone: Setting up an app for use as an "In App Purchase"
body: <p>Regarding In App Purchases, I can find a lot of information on all the technicalities of actually making purchases and interacting with the store (how to retrieve product information, verify receipts, etc), but I can't seem to find information on guidelines or special instructions for preparing the actual "apps" or "components," whatever they're to be considered, which will act as the In App Purchases.</p>
  
  <p>For instance, once a component is downloaded into an app, where does it exist in the overall architecture of the app? How do they combine to join forces? How do they know about one another. If I have a game, and using In App Purchases I allow users to both download new levels, but also download new game play modes that can affect any of the built-in or downloaded levels, how do I prepare all of these assets so that they integrate?</p>
  
  <p>I'm not looking for a tutorial, per se, but would love to know if anyone has had experience with In App Purchases or knows of a useful reference besides Apple's In App Purchase programming guide which only speaks to the specifics of making the actual download transaction.</p>