I dive this site often out of convienience...Agreed with most of the area having a sandy bottom, but as others mentioned the east end of the beach has a great reef! I just dove it yesterday and saw a very large Bat Ray, several Horned Sharks, Lobster, Nudibranchs, Bass galore along with Sargo, Kelp fish, Halibut, Abolone and other life. Park on the far east end (note - the beach faces south out to sea) and gear up. Walk as far east as you can and enter between the two large rocks (about 20' or so high) and enter. If during high tide, watch for some smaller rocks that can trip you up. Surface swim south out to sea about 200 yards or so and look for the kelp. Drop down and enjoy. I usually plan my dive this way then when I'm about 15 minutes from ending my dive, I head west along the 20 fsw depth and still seem to find plenty of stuff in the muck. There are a few small reefs along the way and follow the countour lines in the sand as your guide (instead of staring at your compass). When you are nearing your surface time, swim north to about 5fsw and stand up. You'll avoid the walk in the sand while geared up and enjoy the easy exit.
Once you are done diving, walk over to the showers next to the restroom and rinse gear if you like. I bought an annual pass since I dive there frequently. When other spots suck, this place usually is diveable. The location I described is also known as "Inspiration Point" in one of the divebooks. Little Corona is a similar dive site, but screw that hump of a hill with all the gear.
Another note is you need to recognize the July 4th is a VERY BUSY beach day for the Newport area. You will most likely be directed to the east end anyway by the lifeguards if the beach is full or filling up.
After you dive this site (providing you do) please let us know what you think.