I've been tasked with creating a magazine style app for iPad. Ideally it would look a little something like the Zinio app: http://www.zinio.com/ipad/ . This app is effectively a shell, allowing you to sample magazines (eg. read the first few pages) and select them for download. The magazines appear to have some sort of overlay, allowing you to interact with some things (eg. tap to watch a video). A few questions that come to mind:

1. How would I go about delivering content to the user? In-app purchases aren't really an option, as some content will need to be delivered for free. Is it possible to download a package and make this available within the application?
2. What format would be suitable for displaying the magazine? Sequential images, PDF, ebook?
3. I'll need to have some form of interactivity. I guess I could have some form of lookup table, which would include information such as if the user taps on this page, within these coordinates, then launch this item.

Anyone dealt with any similar issues?