Cross-platform multiplayer game app for the iphone and droid

I have a multi-player artillery-based game I'd like have programmed to be able to be played across the iPhone and Android smartphones. I would like this to be done without needing to use my own server. Being able to create and join matches with and for random people would be preferable to have included, but I would like to be able to contact and play friends at the minimum. It would also need hot-seat and AI options. Most of the artwork, sound fx, music, and data tables would be provided, but some graphic effects would need to be coded (examples would be provided for these). The game must be code-driven not graphics-driven, that is, I want it to already know what happened after a player takes their turn and before it is is displayed on the screen. I also want it to be clean and understandable code, so that somebody else may be able to update it if you are not available. Qualifications need to include: - Previous multi-player apps - Previous cross-platform experience - English proficient - Knowledge of how to incorporate basic physics into an app (power, trajectories, gravity and wind) - A complete Freelancer profile