TILE.NET/LISTS  
   One of the first and largest mailing list directories on the web.
   http://tile.net/lists/

listTool  
   A directory of lists that includes an easy way of subscribing and unsubscribing to them.
   http://www.listtool.com/

DiscussionLists.com  
   Email communities grouped by general topic. Submission form available to suggest new listings.
   http://DiscussionLists.com/

AtoZintheMail.com  
   Provides newsletters as requested.
   http://www.atozinthemail.com/

Public Mailing Lists Managed by Arrow  
   A frequently-updated list of publicly accessible mailing lists managed by users of Roger Smith Software's Arrow Mailing List Server.
   http://www.jadebox.com/arrow/list.html

WebScout Lists  
   Email newsletters and discussion lists which enables subscribe and unsubscribe requests via a simple shopping cart.
   http://webscoutlists.com

Dolist.net  
   References all mailing list types, discussion, diffusion, newsletter, e-zine, alert bulletin, and newsgroups.
   http://directory.dolist.net/annuaire_en.asp

I Want Newsletters  
   A large collection of free newsletters sorted by category.
   http://www.iwantnewsletters.com/

CataList  
   The official catalog of LISTSERV lists.
   http://www.lsoft.com/lists/listref.html