[ http://actioncertification.org/ ]
Offers free personal trainer certification as well as other resources such as business plans, help videos and insurance.
National Association for Fitness Certification
[ http://www.nafctrainer.com ]
Offers a number of certification programs covering wellness, pilates coaching and nutrition.
[ http://www.nialondon.com/ ]
Provides information on the fitness technique and how to practice it in London, UK.