Shadow Shopper is a good site, but you do have to pay to join. I apply to mystery shopping companies all the time, about 3 a day now. I have applied to some that do not shop my area NJ, but others that I applied to do. The trick to mystery shopping is to apply to as many companies as you can and check the job boards often. Just becuase a company doesn't shop your area right now doesn't mean they never will, I see that most shopping companies are rotated for the locations and jobs offered. You might like to check out Volition.com, walletboosters.com and mom-mom.com/mystery they list hundreds of shopping companies and I'm sure that some of them work in your area.
Mike