Bar code scanning

On iPhone:
http://stackoverflow.com/questions/838724/is-there-a-barcode-recognition-framework-for-ios
and on Android:
http://stackoverflow.com/questions/4086794/is-there-any-simple-1d-barcode-reader

Cross Platform?

Programming for both android and iOS at the same time would be preferable but not realistic according to many programmers on the web

StackOverflow thread

Third party cross platform framework

http://www.cocos2d-x.org/projects/cocos2d-x/wiki

Just found this. looks promising!

Research links

Links from background research for cross platform development
NDK for Android:
http://developer.android.com/sdk/ndk/index.html
Designing widgets for Android:
http://android-developers.blogspot.com/2009/04/introducing-home-screen-widgets-and.html
Arstechnica article on NDK support in Android:
http://arstechnica.com/open-source/news/2009/06/android-goes-beyond-java-gains-native-cc-dev-kit.ars
Creating Java wrappers for C++ files:
http://java.dzone.com/news/how-bring-your-venerable-cc-co