mack - 3:39 pm on Jan 14, 2013 (gmt 0)
Every platform will have its own guidelines, and Apple in particular is very reserved when it comes to apps that can download files at a later point in time. The main reason being if an app can download files after its been accepted for app store placement, it may later download malicious code.
There are IDE's that allow you to develop your app, then compile the code for the target devices. Appcelerator and Phonegap are such examples.