California has just passed a 'hands free law' in an attempt to crack down on distracted drivers. However, you're still allowed to use headsets, so feel free to text message and dial while you drive, because that's MUCH safer.
If caught chatting on your phone, a local friendly officer of the law could fine you $20 - $50. California is not the first to pass a 'hands free law'. The state joins New York, New Jersey, Connecticut and Washington.
However, the law does provide some leeway for a couple of situations: "It's an emergency," "I'm a trucker," or, "I'm a tow truck driver." Personally, I would try to use the last excuse.
Interestingly, headsets are still allowed, introducing my personal question, "What's more dangerous, holding a phone or dialing while you drive?" I've enclosed an article from a year ago about a girl who used her phone NINE times before crashing into (and killing) a little old lady.