Cowboy Magic Detangler works great. You might find it locally at any equestrian type store. Petsmarts that have a horse section often carry it. Otherwise you can order online. A little goes a very long way. You can also mix it 1/2 CM with 1/2 water in a spray bottle, shake very well and use it as a grooming spray. It's like oil and water so you need to shake it very well. Here is a link to the CM website:
Cowboy Magic - Detangle Your Hair