List of Used Sail Inventories:

http://www.sailexchange.com/
http://www.usedsails.com/
http://www.minneysyachtsurplus.com/
http://thesailwarehouse.com/cgi-bin/web_store.cgi?page=storeframe.html&cart_id=
http://www.cast-aways.com/jibs.htm
http://www.baconsails.com/database/formkiosk.php?sailtype=102&luff1=35&luff2=38&foot1=1&foot2=30
http://www.sailingtexas.com/chowtopatchasail.html
http://www.sailoft.com/headsail.htm

I got my new furling genoa here:

http://www.mastheadsailinggear.com/UsedSailSearch.aspx

This site has a very comprehensive list too:

http://www.sailingtexas.com/csails.html

This is the marine exchange in Sidney, BC:

http://theboaters-exchange.com/index.php?location=sails

This is the Marine Exchange in Steveston, BC:

http://www.marinersxchange.com/sail_inventory.htm