There are several Internet directories out now.  One recently caught my
eye--probably because it has a favorable review of SCREEN-L.  <blush>
 
Abbott, Tony, ed.  INTERNET WORLD'S ON INTERNET 94:  AN INTERNATIONAL GUIDE
TO ELECTRONIC JOURNALS, NEWSLETTERS, TEXTS, DISCUSSION LISTS, AND OTHER
RESOURCES ON THE INTERNET.  Westport, CT:  Mecklermedia, 1994.
 
At $45 (paper) it's probably priced more for libraries than individuals.