I just posted this message announcing the release of Moodbile 0.2 beta. Since it has a lot to do with webservices thought to reference it here.
I don't want to clutter the forum but let me paste the part I beliebe is relevant for this forum:
Moodbile Spec is a specification of (web)services for supporting the integration of external apps with the LMS. The Moodbile Spec(web)services are not bound to a specific Webservices protocol. The Services need to be implemented in the LMS side.
Moodbile Server for Moodle - Moodle 2.X plug-in that implements the Moodbile Spec. Current version Moodbile Server for Moodle v0.2 has been tested for Moodle2.0.5 For support for other Moodle versions check the Moodbile roadmap.Moodbile server for Moodle includes some new webservices connectors (compatibles with the Moodle Webservices Architecture) JSON-AJAX, JSON-P With OAuth Authentication, JSON-RPC, JSON-RPC With OAuth Authentication, REST With Oauth Authentication. While the services sitill work with the current Moodle webservices connectors.
Hope it is of interest.