I have known two people with this phobia, and interestingly, they dealt with it in quite different ways.
One, a work colleague, had always been absolutely terrified of any medical procedure. Her approach was to view it as papiermache describes -as very much not a medical procedure, but a natural event which would be hard work and would involve pain, but which would ultimately be the only way to getting what she really wanted - her own baby. This woman booked into a 'home from home' birthing centre, and had a straightforward delivery, I believe she had gas and air and used a birthing pool, and described the birth afterwards as 'not as bad as she expected'.
The second woman, a relative of mine, went to the other extreme and from the very early stages of pregnancy, agreed with the hospital that she would opt for the medical route. The hospital she chose was very supportive - they agreed to give her an epidural as soon as she admitted herself, even if it was very early stages and she wasn't in a huge amount of pain. She ended up with a birth she was happy with too.
So, it seems the important thing is confronting the fear, talking to the experts and deciding on which is the best route for you. Is the fear about the process itself, or is it more about the pain? Looking back, I can see that with my relative, the fear was all about the pain, and once she knew she could have a pain free birth under epidural, she was fine, even though it was a far more medical event and she needed ventouse to get the baby out as of course she could feel nothing. My work colleague, on the other hand, had a fear of the process rather than pain, and for her the right way was to demystify the whole birth process and realise that it's a natural event.
I would definitely recommend talking it through with a speicialist.
Good luck