Hi Joe,
I shore dive San Diego 2-3 times a week, and even with tide charts, you never know what you're going to get until you get there.
I agree with others comments, hook up with a DM from a local dive shop, such as;
Aqua Tech (619) 237-1800 or
Ocean Enterprises (858) 565-6054
Also, as mentioned GottaDive.com is an excellent source for boat dives to the Coronados or kelp.
That said, the safest place to Shore dive is usually La Jolla Shores, it's where most dive classes conduct their open water training. I still would not go there without a DM or local diver familiar with the area and conditions. It is an open sand area, dropping down into a deep canyon with walls and outcroppings. Plenty of small life for the knowledgable to find, but for someone not familiar (usually moving too fast) it unfortunately will look like bare sand or canyon walls with nothing there to see. :11:
Here's a couple of photo links to photos I took Sunday in the canyon, so there is life there!
http://dive.scubadiving.com/members/photogalleries.php?s=5468
http://dive.scubadiving.com/members/photogalleries.php?s=5469
Other good spots include a shallow reef south of the Marine Room in 20-30 fsw, or La Jolla Cove, with beautiful reef structure and kelp. The Cove is a steep shore break, so depending on conditions, a DM may not take you there. The Marine Room has the same entry conditions as La Jolla Shores, but the shallow reefs can create problems if the swells are large or close together. Express your diving desires to the DM you hook up with, and I'm sure they can take you someplace you'll truly enjoy.
If you know about what time of the day you'll be doing a shore dive, I can give you the tide conditions, and make a recomendation based on that info. It won't be perfect, but it'll at least tell you where to avoid.
John A.