Jim Steele owns a shop called Steele's Discount in Oakland off Telegraph Ave.
He runs his shop more like a friendly neighbor than a store owner. The best part about him is that he wants to teach people how to dive and he wants to save divers money ;D.
My dad took his basic OW there.
My only complaint is that while he teaches NAUI and certifies you via the NAUI exam, he doesn't provide you with a NAUI book to buy. Yet you still get the info you need via him and various other books he has. It's a full NAUI basic course, sans the NAUI book.
Also if he doesn't feel like you're ready, or if you don't feel like you're ready, he won't take you out for your basic checkout. But you will be able to attend the next class's pool sessions and checkout dives free of charge until you do finally get certified.