CGDB is a very lightweight console frontend to the GNU debugger. It provides a split screen interface showing the GDB session below and the program's source code above. The interface is modelled after vim's, so vim users should feel right at home using it.
Screenshot, downloads, and documentation are available from the home page: http://cgdb.github.com/
Official source releases are available in the downloads section, but will be moved soon (since Github is killing this feature): https://github.com/cgdb/cgdb/downloads
This README will be updated with the new location when suitable hosting has been found.