The thing is that there are many answers. You can go through informed consent or you can get a letter and then get a prescription. My doctor who gave me the prescription was a family practice doctor. I've heard of gynos, general practice, and endos being able to start you on hormones.
I had to call over 50 doctors even after having my letter to find one. Just keep calling around man. Don't give up hope. Checking in with your nearest glbt center could help because they may have suggestions for you. If your interested in getting the letter then just call as many psychologists/psychiatrists as you can find. Also, where I'm at I find that a lot of "sex therapists" tend to handle transgender/transsexual patients so that might help? I'll see if I can help find anyone specific for you. Good luck

Edit: Here's a link for trans friendly therapists just look up your state
http://www.drbecky.com/therapists03.html