If you're looking for some great free data on home values and rental prices for your specific area then definitely check out this website. Zillow.com (now owns Trulia.com) is the leader when it comes to guesstimates and trends on values for prices and rents. Did I mention it's free??
With that said be sure to use common sense when trying to value your home and/or figuring rental prices. Look at comparables and look at the trends of what have been happening. You'll probably find that your place will sell or rent for higher than they suggest. Either way it's great data to play with.