From Arduino blog:
Programming arduino using your smartphone? Indeed! It is possible if we have the IDE in HTML5. With similar thoughts Tadpol started building a browser based AVR compiler. The project is still open for contribution at Github. Hackers, please contribute!
This project uses a ladder language to input the code and then it's possible to program your AVR using a WAV file, connecting it to your audio port. The idea is to make arduino development possible on any smartphone.