You can also fly into Long Beach (LGB) - a short drive on the 405 and closer to the OC than LAX.
Were you hoping to just stay somewhere in the OC on the weekend or did you actually want a beachfront hotel? The OC is a big place - a bit of your preferences would be helpful in narrowing it down for you.
You might also consider moving this to the Southern California forum - you would likely get more locals responding.