Catalist

Catalogue of LISTSERV lists.

DisucussionLists.com
A directory of email discussion lists and communities on the Internet.

Internet mailing lists: Guides and Resources
Maintained by International Federation of Library Associations (IFLA). Includes information on netiquette and frequently asked questions.

Ozlists
A service provided by Griffith University. Ozlists is a directory of non-commercial electronic mailing lists based in Australia or primarily concerned with Australian content.

Tile.Net Lists
A guide to email newsletters and discussion lists. Also has a Google search facility.