I think Global Fitness Educators are one of the best Kettlebell Training & Certification Providers in USA. You can visit them here http://globalfitedu.com/
A certification course that is missing in Phillip’s list is the ATSCI kettlebell lifting instructor course www.atsci.org . The method taught at that course is performance oriented rather than purely calorie expenditure focused. The course came to be after a presentation I was doing at the NSCA TSAC (tactical fitness). A team of Navy SEALs from Coronado participated and asked me if I could teach them and certify them on my method. We had our first course at the Colorado State Patrol Training Academy a year after that. Since then we have been serving Special Forces, SWAT, and Fire Fighters. Coaches and personal trainers have also taken interest and we are seeing more in the courses.
The course is worth NSCA 1.5 , ACE 1.4, and NASM 1.6 continuous education credits. There is testing, remote assistance to prepare and strong emphasis on programming and injury prevention.
Feel free to call or email with questions. I just wanted to add this to the excellent reply from Phillip since we weren’t represented. I hope this helps.
A non as famous but one that is used by high level athletes and special forces is the one in Colorado. The website is www.atsci.org and the main instructor is Nico Rithner.
I hope it helps!