Community Sites
http://www.loaches.com - An excellent site for any loach species imaginable. Special note to the comprehensive Species Index and the Web Forum.
http://www.aquariacentral.com - A large database of Fish species with a large collection of forums
http://www.thekrib.com - An excellent source of information about all things fishy
http://www.fishprofiles.com - Excellent site for tank planning! Reasonable fish species index, with an excellent "find compatible species" search function makes this an extremely helpful place for ideas.
Retail Outlets
http://www.wep.itgo.com - Worlds Exotic Pets, a local outfit run by some of the most dedicated animal and reptile lovers I have ever met. If you are on the west coast of Canada I would highly recommend giving them a call.
http://www.bigalsonline.com - Very large Web retail chain with lots of everything
Personal Pages
http://www.lunarpages.com/bobd/loaches/ - Bob Darnell's collection of loaches, excellent photos
http://www.geocities.com/mophir/ophirpage.html - Loach photos and articles Mike Ophir has written