If not, you will soon. Zillow is the most compelling website I've seen yet for valuing and comparing real estate. They have more than 67 million homes in their database, and you don't have to register to use it. You can find out what your home (or any home) is valued at on the market, you can see an aerial view of its location, and track its value over time. If you own a home or if you're considering buying one, you must check them out on Zillow.
(Sounds like I own stock, doesn't it? Wish I did. Maybe I should. . . )