Good plan Zoe. While there are some indications that in MA and NH, we've passed "the bottom", only time will tell if that's true. In any case, sale prices are still the lowest they've been since 2004, and if you can wait to sell even for a year or two, you *may* see increases in price. Of course the crystal balls are still cloudy on that (even for us Realtors!) but that is the general consensus... 2009 to stay somewhat flat, with very slight gains coming in for the spring 2010 market. We shall see...
Anyway, if your condo is between Nashua and Manchester, I'm guessing it's in Merrimack? Your best bet is to either ask a real estate agent to list the property in MLS, and he or she will help you screen potential renters. The cost for an agent to do this is usually 1 month's rent. If you prefer to rent it on your own, check rental prices on craigslist or look in the local paper or check NNEREN.com for comparable rentals. Good luck