First check for recommendations from people who have used a homeopath in your area. If you don't know of anyone, try the NCH study groups for references. The people always seem to know who's good and who's not so good.
You can search in the NCH practitioner directory but remember that anyone can join so it's not a good indication of quality.
Other directories available to search are the American Institute of Homeopathy and the Homeopathic Academy of Naturopathic Physicians.
Steve Waldstein is also well-known for his list of what he recommends and is worth cross-referencing. If your guy isn't there, it might be worth asking why.
Another good idea is to do a Doctor Search for $10 to check references if they are a doctor. And I can't recommend any homeopath who is willing to work with you solely by e-mail or phone. They make great follow-up tools but homeopathy is based on seeing the patient and seeing the symptoms.