Like Dan says, yest the general rule is 2 years. But there are other things to consider, if your current loan is FHA and you go through with a short sale, it is my understanding (local lender and I had this discussion last week)that you will never be able to finance FHA again.
I would recommend that you speak to a lending officer in any case.
The general rule is 2 years, but there are programs for some short sale sellers which under the right conditions allow them to buy sooner. You'll need to talk to a local lender familiar with all the details of your situation and the available programs to find out if you qualify.