A quick search on the net brings up a number of articles which highlight key design differences between designing Iphone and Android apps.A list is given below :
Why do apps from the same company look worse on Android than on iPhone? - this is more of a gripe but then I guess it could be due to a matter of personal preferences of expected behavior
Comparing Common iPhone and Android UI Conventions : I like this link since it gives me information about the design differences between designing for apps for Iphones and androids and what the aspects you should keep consistent such as the icons and notifications on the top and the bottom of the app
11 Screenshots That Prove Android Apps Are Uglier Than iOS Apps - Highly subjective but provides some interesting views
I know this was not the answer to the question since you were specifically looking at apps which were available on both Android and Iphone but I felt the above articles would provide some insight into the views of people and what they expect from an android/iphone app.However for comparative screenshots,your best bet would be to the app developers site/app store and see the screenshots there.