MP3 encoder mailing list
For general discussions and comments about LAME and MP3 encoding, you can check the MP3 encoder mailing list. Keep in mind this is not the preferred list if you want to get in touch with the developers.
LAME development mailing list
The lame-dev list is right place for everything related to LAME development: bug reports, questions and suggestions concerning the encoder, the documentation and the web pages. It's also the best way to get in touch with the active developers. Archives are provided by SourceForge.
CVS mailing list
If you want to be automatically notified of commits to CVS, you can subscribe to the lame-cvs list.
Some developers and other interested parties can eventually be found on the #mp3encoder channel on the FreeNode Network.
To submit bug reports, you can use the bug tracker besides the lame-dev mailing list. Please be descriptive in your bug report. You should clearly mention your problem, LAME version used and how to reproduce the bug.
Here is the list of developers. If you encounter a problem, please use any of the ways mentioned above instead of directly contact a developer.