File, track, and vote on bugs and feature requests. There is issue tracking for MongoDB and all supported drivers.
http://groups.google.com/group/mongodb-announce - for release announcement and important bug fixes.
The events page includes information about MongoDB conferences, webcasts, users groups, local meetups, and open office hours.
The source code for the database and drivers is available at the http://github.com/mongodb/.
This mongodb-dev mailing list is for people developing drivers and tools, or who are contributing to the MongoDB codebase itself.