First aid certification is a necessity for any personal trainer. ALL personal trainers MUST have a valid first aid certificate in order to practice. There are many independent first aid training providers, below are some recognised bodies that may be able to assist you.

Useful First Aid training links...

http://www.nremt.org/about/nremt_news.asp
http://www.employerhealth.com/EHR_sample_pages/dpstrf.htm