Well, the most accurate way to find comparison properties in your area is to contact a professional Realtor. They can create a Comparative Market Analysis (CMA) for you. If you don't yet feel comfortable doing this, you can search for houses on any national real estate site for houses in the area you are interested and start comparing them side by side. Of course this can be tricky since most houses aren't going to be exactly the same, which is why you probably won't get quite as accurate a result. However, for research purposes it will give you a start.
Let me know if you need help!