With a degree in exercise science, and experience in physical therapy, I would think that would be more impressive than training. What are you planning to do long-term?
If you want to train to gain another notch for your resume, then I'd suggest getting a certification from one of the more respected agencies (NASM, ACSM, ACE, NSCA) - which I highly doubt would be a problem at all for you.
From there, contact gyms in your area and see what their policies are with trainers, as they can vary (employee vs independent, work a set time frame vs make your own hours, etc).
You could also look into marketing techniques, etc (there are books and such available) that could help you in that area, to help build a client base.