How can I get more comfortable with the idea of giving birth?

Information. Find out what makes you uncomfortable about giving birth and concentrate on those aspects. Are you concerned about pain control? Talk to the anesthesiologist at the hospital. Maybe tour labor and delivery before you deliver to see the rooms and meet some of the nurses. Making yourself familar with the environment may ease some anxiety. Attending birth classes may also help.
Talk. Talk to your ob, midwife, birthing center personnel. Talk to other mothers, join classes like lamaze classes where you can meet other mothers...