I’m not a designer and when for the first time I tried to create an app (Nearby Photos) I faced the problem of creating a decent user interface.
That problem has not yet solved for me, but I found a interesting site which collects a great number of designs for mobile application. From galleries to empty data set layouts, you can find your inspiration.
The site is “Mobile Patterns” and even if there is not ready iPhone or Android code nor PSD files, you can find some interesting patterns and skip the step to decide how to organize your app contents.
Take the time to look at it, it’s quicker than install tons of apps to see how they look.