Since indexers are generally few and far between, you can find a great deal of support by joining an indexing society. Here is a list of names and addresses for English-speaking indexers:

American Society of Indexers
10200 West 44th Avenue, Suite 304
Wheat Ridge, CO 80033
Voice: (303) 463-2887
Fax: (303) 422-8894
E-mail: info@asindexing.org
http://www.asindexing.org

Australian Society of Indexers (AusSI)
PO Box R598
Royal Exchange
NSW 1225 Australia
Phone: +61 0500 525 005
E-mail: memsec@aussi.org
http://www.aussi.org

Indexing and Abstracting Society of Canada/
Société Canadienne pour l'analyse de documents (IASC/SCAD)
P.O. Box 664
Station P
Toronto Ontario M5S 2Y4
Canada
http://www.indexingsociety.ca