The RegLookup project is devoted to direct analysis of Windows NT-based registry files. RegLookup is released under the GNU GPL, and is implemented in ANSI C. RegLookup provides command line tools, a C API, and a Python module for accessing registry data structures. The project has a focus on providing tools for digital forensic examiners (though is useful for many purposes), and includes algorithms for retrieving deleted data structures from registry hives.
See the main project site. You'll find official releases there and more documentation.
Ask for help on the development mailing list or submit a ticket.
RegLookup is largely feature-complete for what we wanted to accomplish. So the releases are infrequent (typically only when bugs crop up), but the project is still maintained.
We love contributions. To submit a patch, please check out the trunk, apply your changes and run "svn diff
". Save the resulting diff and attach it to a ticket.