View Source Code of Existing iPhone Apps

The files uploaded to the iTunes store are only those included in the .app package. These include all the resources, so all the .nib files would be there, but there's no source code in that package as far as I know. You can view the package you would upload by expanding the Product folder in the Xcode Groups & Files tree. Then Ctrl-click on the .app icon, select Reveal in Finder, Ctrl-click on the .app package and select Show Package Contents.

Lots of independent developers (as distinct from corporation employees) are willing to share their knowledge including excerpts from their code, and that's what this forum is all about. I've pasted lots of source code from my app into the answers I've provided in this forum. If you contact a developer privately, I think it would be better to ask "How did you do that?" instead of asking for the complete source code. But there are lots of people out there who enjoy teaching others even more than protecting their ideas. My only disappointment in this forum is that many (but certainly not all!!) are really good at saying "please", but seem to have some language problem with "thank you".

Oh... I meant to say, "You can see the contents of any package you build with Xcode...". I don't know of any tool for examining the module that iTunes downloads from the store for installation on the iPhone. There might be a tool like that, but apropos our earlier discussion, I'm guessing the format is proprietary and I wouldn't expect Apple to be enthusiastic about supporting a reader. Could be wrong about that, though. Usually when I post bad info in these forums, a corrective response is swift and often without mercy, so we shouldn't have long to wait.

Btw, you can quote from the message to which you're responding by clicking the double-quote icon just under the Compose tab on the Post Message page. That feature can also help you learn lots of other formatting tricks here, since it will expose the raw text of any message you choose.

You can contact the developer and ask to see the source code. Otherwise, no, and if there were such a way no commercial developer would ever make apps for that platform.

Compiled languages are a one-way street.