There are a lot of questions here that could change your best course of action. For example, if you purchased the second home as an investment, knowing that you would subsidize the loan payments in order to gain equity, then you might want to hang onto the property because the current drop in prices may have little impact on your long-term prospects for making money. Much as one who buys a company's stock can lose money the first week, only to gain much more over the next year, your second home may lose money in the short run, only to gain that much and more back in the longer run. If the long run prospects still look good to you, then you might want to ignore the current situation.
On the other hand, if you are like some people I know who moved to a new home and had to rent the old residence because of the recent drop in home prices, then you may want to take the more expedient route of checking into a short sale. In this case, the sooner you get the ball rolling, the sooner you will sell the house and get out from under the financial burden. Also, your credit score will bounce back sooner.