The principal trade publication for the field of Management Consulting is called
Consultants News, and there's a publication called "Consultant,"
which is readily available online.
Consultant News is published by Kennedy Information, which has a Web
site with a little content (www.kennedypub.com),
including a list of the 40 largest management consulting firms. Kennedy Information
welcomes telephone calls (1-800-531-0007) for the purposes of selling their
directories and publications.
Other possibly better sources of information include the Association of Management Consulting Firms (212-697-9693) and the Institute of Management Consultants (212-8262).