Most dive shops offer PADI and NAUI certifications. It doesn't hurt to compare them. It is also important to choose an instructor that you trust and feel comfortable with. She should be thorough, patient, and supportive. Don't stick with someone you are not comfortable with.
Scuba diving is a dangerous sport.
You need the proper training to be successful and safe. Now you are probably wondering how long the courses are and how much do they cost. First, the course length depends on you and your schedule. If you had nothing but free time on your hands, you could be a diver in two weeks. But, must of us work and leisure time is a rare commodity.