This firm will hand wash and clean sails up to 7,000 sq. ft. Also cleans and waterproofs biminis, sail covers, awnings, etc.
Short definitions for several dozen terms used in defining sail cloth, including brand names.
Makes laminated and woven sailcloth, sold primarily to sailmakers. Their site has lots of useful pages on choosing sailcloth, finding a sailmaker, getting the most out of sails, caring for them, and more.
Note: Looking for sailmakers? Unless they offer an unusual sail cloth, all sailmakers are shown under the more general topic, Sail Construction
Here's a tour from woven to laminated, Dacron to Vectran. The choices are many and diverse, but "Get it wrong and you will be saddled with a sail rife with potential problems." 3 pages.