American Society of Indexers (ASI) 
Professional organization in the United States solely devoted to the advancement of indexing, abstracting, and database building.
http://www.asindexing.org/Australian and New Zealand Society of Indexers (ANZSI) 
Contains society details, list of available indexers, monthly newsletter, and links to indexing-related resources.
http://www.aussi.org/
American Society of Indexers (ASI) -- Tennessee Group 
Serving the needs of indexers and the indexing needs of the public.
http://members.aol.com/tennwords
American Society of Indexers (ASI) -- Massachusetts Chapter 
Indexing information and resources for experienced indexers and those interested in becoming indexers, workshops, meetings, and conferences on indexing, marketing, small business and freeland consulting issues
http://www.marisol.com/maasi/
American Society of Indexers (ASI) -- Science and Medicine SIG 
An alliance of skilled professional indexers with backgrounds in medical, engineering, and scientific fields. We work in a variety of formats including back-of-book, CD-ROM, and online systems.
http://www.scimedindexers.org/
American Society of Indexers (ASI) -- Florida Group 
Mailing list for indexers in Florida.
http://groups.yahoo.com/group/FLIndexers/
American Society of Indexers (ASI) -- Culinary Indexing SIG 
Special interest group for indexers of cookbooks and other books on food and cooking.
http://www.culinaryindexing.org/
American Society of Indexers (ASI) -- Pacific Northwest Chapter 
The PNW Chapter of ASI serves members in the Pacific Northwest (US), as well as providing general indexing information to publishing professionals and organizations in the region.
http://www.indexw.com/pnwasi/
Society of Indexers (SI) (UK) 
Includes information about membership, publications and activities of the Society; indexing as a career and training courses, as well as information about indexing for publishers and authors, including guidance on fees.
http://www.indexers.org.uk/
Society for Technical Communication (STC) -- Indexing SIG 
A special interest group for writing professionals who index their own documentation or are interested in doing so. Past issues of the SIG's newsletter are available online in PDF.
http://www.stcsig.org/idx/
American Society of Indexers (ASI) -- South Central Chapter 
The South Central Chapter of ASI represents indexers in Texas, Oklahoma, Arkansas, and Louisiana.
http://www.asi-scc.org/