I use Dawn dish soap to clean my dogs. It's safe for animals and the most effective "flea shampoo" I've found!
It's good for fleas and general cleanliness, but I also supplement my Samoyed with those skin and coat treats. I have to get more, and can't remember the brand, but I buy the stuff that comes in little brown bags. The treats themselves are small and bone-shaped, and they have a very rich smell. Charlotte gets two a day and I don't understand how it works, but after not taking for awhile it only takes two weeks of two-treats a day to see a noticeable difference in her coat! Her fur looks cleaner and shinier, there's less build up of skin oils, and her over coat is much softer.