Barbara Ballard’s mobile patterns library has become a wiki for all to contribute to and help develop.
“Designing mobile user interfaces grows ever more interesting. Device and network capabilities are improving, platforms are giving us more features to help the user, privacy and security are becoming more important, and device proliferation is both increasing and decreasing. This wiki aims to be the authoritative resource for all things related to the art and science of mobile user interface design. While it is maintained by Little Springs Design, content comes from various sources and is shared freely (see license info at bottom of the page). Please use, reuse, and edit.”
Update (10/5/2011): The Wiki at Little Springs has disappeared, but there are some new mobile ui pattern resources here.
Link: Main Page – MobileDesign (littlespringsdesign.com)