Human shampoo will clean a dog. I even use human conditioner on my dogs sometimes. Some people say to use dish soap but that really dries out their skin and pulls the natural oils out of their fur. Dawn does help if fleas are an issue though.
Dawn dish soap (original blue) is the best -- used by vets all over the world and what is used to remove oil from the animals trapped in oil spills. It is used by vets on kittens under 6 weeks of age to remove fleas (it kills them instantly).
If you do not have Dawn, you may also use human shampoo, but be sure to rinse very very well as the residue can dry the dogs skin. Do not use human conditioner though. It is too oily for dog fur and will not rinse very well.
I am a vet, and NO DO NOT use dish liquid. It is severely drying to the skin and can even cause hives and a rash. Canines coats aren't normally oily and that's how they get away with bathing once a month. I suggest Johnson's baby shampoo, or any Aveeno shampoo because it contains oatmeal and is scent free