Dancer Organizations:

Tam Twirlers Square Dance Club
Bay Area Club Listings (North Bay)
Bay Area Club Listings (South Bay)
Northern California Square Dancers Association (NCSDA)
Santa Clara Valley Square Dancers Association (SCVSDA)
Associated Square Dancers of Superior California (ASDSC)
California Square Dance Council, Inc.
United Square Dancers of America
Single Square Dancers USA (SSDUSA)
International Association of Gay Square Dance Clubs (IAGSDC)

Caller Organizations:

Square Dance Callers Association of Northern California (SDCANC)
Santa Clara Valley Callers Association (SCVCA)
CALLERLAB
American Callers Association (ACA)
Roundalab

Other useful links:

Vic Ceder's Caller Database
Western Square Dancing