See also Search Engines & Webrings
What is a Listserv? simple pictogram description, scroll down the page to see it
Listserv Tutorial basic info about listservs, how to subscribe, etc.
Mailing List Management Programs (List Servers) gives a few more technical details about listservs
Topica (formerly Liszt Directory of E-Mail Discussion Groups) search for listservs
CataList search for listservs
Directory of Scholarly & Professional E-Conferences free online searching
Tile.Net Internet Discussion and Information Lists search for listservs
JISCmail: National Academic Mailing List Service "facilitating Discussion, Collaboration and Communication within the UK Academic Community and beyond"
Children's Disabilities Lists of Lists
Yahoo! Groups use the search feature to find groups on your topic of interest
Google Groups click on "Groups;" use the search feature to find groups on your topic of interest