I am extremely interested in becoming a CRNA.

I have been researching schools to better prepare for admission as soon as I am eligible. Right now I'm taking the pre-reqs for nursing school and I expect to be admitted in Spring 2007. I see that some schools offer a master's of science in nurse anesthesia and others have a master's of science in nursing with a certificate/concentration in nurse anesthesia. What is the difference or rather the pros and cons?