Zentyal Team is glad to announce that an updated version of the Zentyal module development tutorial (for Zentyal 3.0) has now been published in the community wiki. The tutorial offers an easy-to-follow, practical guide for developing new Zentyal modules and extending the existing features.
If you would like to get started, but are not sure what module might prove popular, take a look at http://ideas.zentyal.org This tool has been set up to make it easier to submit, vote and track ideas for Zentyal server development. You can pick any idea from here and get started!
If you have any feedback or questions, please let us know through Zentyal Forum or Development Mailing List.