Go to
www.akc.org or
www.ukcdogs.com . Search the club listings for an obedience club near you. The clubs are listed under the "dog events" tab on the UKC website.
The instructors at the clubs have trained their personal dogs to obedience titles. Some have over 20+ years experience training and instructing. You will find different training techniques versus only one way at Petsmart/Petco.
For an example of a typical training club check out
www.tulsadogs.com. It's the website of the Tulsa Dog Training Club. I train my dogs and instruct Beginners & Novice level classes at TDTC.
I would skip the choke collar and go with a martingale or a prong collar if your dog is a real puller. I only use a choke collar while showing at obedience trials.