The first draft of a formal spec of our mobile app has been published, for potential volunteer developers. See:
It basically describes the functionality as exactly as possible of the iPhone app, to make conversion to other platforms easier.
If you can help develop our apps, which are on GitHub, with the GPL license, please do drop us a line. Android devs particularly welcome!
The document has not yet been fully checked, and a few missing API call examples (though they just mirror what's online) need to be added, but it is 99% done now.
Please let us have any comments on things that are not clear or where implementation would be ambiguous.
As stressed in the foreword, the spec is merely a template for creative work, not an exact blueprint for implementation, since other platforms will do things differently and the existing app needs changes anyway.