A short sale is one where the title has transferred and the sales price was insufficient to pay the total of all liens and costs of the sale - the seller did not bring sufficient liquid assets to the closing to cure all deficiencies.
In layman's terms...you owe more than the property is worth, so when you sell it, you will come up "short". It doesn't have anything to do with a quick or speedy transaction, in fact, it's just the opposite - it usually takes 3 to 6 months & sometimes longer for the transaction to close.
If you do believe you will be in a short sale situation, the first thing I would suggest is hire a REALTOR in your area that specializes in Short Sales. These transactions require lots of communication and documentation between your REALTOR and your lender. If you have an inexperienced REALTOR (especially on the listing side), it will make the transaction take even longer or it may never sell. In the mean time...you are getting deeper in debt.
When you hire your REALTOR, be prepared to answer some tough questions! Your REALTOR will have you gather information about your assets (real estate, stocks, bonds, bank accounts, etc), liabilities, the amount of our monthly expenses, pay stubs, W-2's, bank statements, supporting hardship information, and more...All of this information will be submitted with your short sale package to your lender, who will ultimately have the final approval on the sale of your house.
Don't lose hope, as REALTORS, we are prepared to handle situations like yours. Just grab your hat & hold on...it's going to be a wild ride!