This book is a great resource. Ellen Amirkhan is a third generation rug cleaner who owns and operates her families 105 year old rug plant in Dallas, TX.
Every year she and Aaron Groseclose, owner is MasterBlend, host many classes through their Master Rug Cleaner programs. These, IMO, are the best and most comprehensive classes offered in the industry.
Nothing will beat getting some hands on education. Check out the ARCS association, they have a Web based program coming up this August. Very affordable and would be great for someone just starting out in rug cleaning.