I just got my PADI certification last month. I did mine with Signature Scuba in Rancho Cucamonga though. The instructor was really nice and knowledgeable. I don't know where you could do it in the OC though.
There are a few different agencies. PADI, NAUI, SSI, SDI, YMCA and the list goes on. Sport chalet with a PADI instructor is probably the easiest to access/pass.
Check out Pacific Wilderness in Orange. I got PADI certified by their shop in San Pedro. They also seem to have Living Social deals for 1/2 off lessons every now and then.
Definitely check out Open Water Habitat. They have the greatest costumer service and knowledge. Gary and Mike are the owners and they have a passion for diving. My father and I recently got certified, my girl friend is now taking her classes. Highly recommend checking them out. They service any old gear you might have so you don't have to buy new stuff from them. They don't try to sell you crap you don't need. Definitely will help you scuba skills when learning from enthusiasts like Mike and Gary.
Check out Pacific Wilderness in Orange. I got PADI certified by their shop in San Pedro. They also seem to have Living Social deals for 1/2 off lessons every now and then.
I have a suggestion. Fullerton College teaches Scuba. Best part is, they have the time and resources to make sure you have a better than basic understanding of how to be safe. The instructor's name is Rhett and a good guy. They can and will rent your equipment for less than some of the other places as well as have many beach/boat dives scheduled every semester.
you dont need to be an Olympic swimmer to become a certified diver all you need to know is how to kick your fin... cuz you ain't swimming like a fish underwater.