US Squash - http://www.ussquash.com/
PSA - http://www.psa-squash.com/
WISPA - http://www.wispa.net/
Rules of squash - http://www.worldsquash.org/rulescontents.html
Intercollegiates - http://www.squashtalk.com/collegesquash/

Other SRAs:
Houston - http://www.hsra.us-squash.org/index.htm
Florida - http://www.floridasquash.com/