Harp-L
- Harp-L is the leading online harmonica discussion group. Particpants include everyone from rank beginners to professional players, and topics range from theory to gear to technique to everything in between. Sign up, yak, and learn!
- http://www.harp-l.com/

HarpTalk-Online Harmonica Discussion Group
- HarpTalk was formed to discuss harmonicas, harmonica playing, and related equipment, as well as to share tips, techniques, and experiences. This is a large group, approaching 400 members.
- http://groups.yahoo.com/group/harptalk/