A good place to start would be at Dive Connection's website at
www.gottadive.com. They have their whole 2-3 months schedule on the internet and also have the ability to book your spot online.
If you like diving wrecks, Yukon will be great. It starts off around 60' and goes down to 100'. It's on its portside, so it's somewhat disorienting when penatrating or looking from close distance.
Kelp is also a good dive. It feels like swimming through a forest. I has a large amount of marine life and is also a good place to hunt (to you all enviromentalist, plug your ears).
Coronado Islands are one of the best. you get great visibilty on most days. However, this place is cold. Coronado Island is like doing a wall dive and a naturalist dive at the same time because of the island's wall that steeps down. on a good day, you'll find a large amount of seals there wait for you to jump in and play.
If you wish not to spend great amount of money or wishes to dive from shore, La Jolla is a great place.
La Jolla Shores is mainly devoted to divers who are new or divers trying to orient themself with new equipments. You'll find many new divers diving this spot over and over to gain experience due to its easiness. classes are held here as well. most of the time, you'll see a large amount of sand...and nothing but sand. sometimes, you'll a huge bat ray that will swim along with you...or away...
La Jolla shores is just up the hill a bit south from the shores. There are a lot of marine life here that you can see. Visibility will depend on the depth you're at. pretty much, everything depends on the time of the day.
A real good dive store to deal with is San Diego Divers Supply. They're affiliated with Ocean Enterprises (biggest dive store in san diego...and likely to be the biggest in the world) but the prices are less. they're very helpful, thus me going back there time after time. they may give you more advice as you ask them more specifically.
more information about san diego diving is located on
www.divebums.com, as stated above.
i hope you enjoy your time in san diego and hope that you'll come back again and share your experience with other divers you meet up with in your area!
Hope my message helped.