Don't do it Vic! Loan mods are garbage. They're non-existant. Miss a payment your credit will drop miss three or 90 days late and you might as well have filed a BK. Lenders don't want to work with you if you're upside down (ie: owe more than it's worth) unless you can make up the difference in cash at the time of closing. Additionally, if you are behind, you will need a hardship letter and even then it's not guaranteed that they'll work with you AND even if they did work with you it's more of a joke than you'd believe, I had one lender tell me that the difference in payment would be something like $100 or so. It was a waste of time and a useless risk of good credit.
As for a short sale, not a good idea. Only people that make money are the brokers. You might walk away but, IIRC - CA is a state that allows for deficiency judgments... And it also ruins your credit. It would suck to not only loose the house and the credit but to also owe money for something that you don't own. If you can't pay today- that's ok they'll put a lien on file and you WILL pay one day...
If the house is way upside down you might be able to file a bk. Be advised that if your credit tanks, it will be a few years before your credit will recover enough so that you will be able to get a decent rate for a new home loan.
Additionally, you may not qualify for a liquidation chapter 7 but rather a chapter 13 which would have you making payments for the next 3-4 years...
All of that will depend on your assets, liabilities and any additional financial issues you might have. It is recommended you hire legal counsel for this so you don't mess it up. It's not cheap. If it is, be careful...
There are various options depending on your situation. Most of them are not ideal considering the current economic climate but, at least there are options...