The best way to valuate a property is to get recent sales/closings from your real estate agent and compare them to your subject property. You will need to make adjustments for things such as condition, livable square footage, # bedroom & bathrooms, etc.
However if you need a quick estimate there are several web pages that offer free estimates. They are:
1. Zillow.com
2. eppraisal.com
3. cyberhomes.com
4. trulia.com
5. homegain.com
6. electronicappraisal.com
7. ziprealty.com
8. totalviewrealestate.com
If several give similar prices, you can use them for a preliminary value. Nevertheless, these are estimates only and I have seen them off by quite a bit; they should be used as a substitute to making your valuation based on recent sales/closings.
If anyone has other web pages to estimate values, please let us know.
Thanks, and good luck.