You have to know how much your house is worth before you put it up for sale. That means paying attention to your neighborhood's real-estate microclimate -- a task that has become easier, thanks to the Internet.

"Up to now, really, when you and I wanted to find a house, find out what was happening in a neighborhood, you would have to ask everybody around and trust the answers they give, or go to the courthouse" to look up property records, says Manuel Iraola, founder of Homekeys, a Web site that offers information about home values. Now, he says, Web sites and the people who use them are becoming sophisticated.

4 ways to track housing values All sorts of information about home values can be gleaned, online and offline: prices paid for homes, mortgage amounts, square footage, numbers of bedrooms and bathrooms, asking prices, and even which direction houses face. Usually you have to chase the data in more than one place. Here's how to do it (not necessarily in this order):

Tracking housing values • Go to the government source • Visit Web sites that estimate home values • Track asking prices and amenities at Realtor.com • Step away from the keyboard and visit comparable homes for sale

Go to the government source
Getting information from the local government can be complicated. States and counties have differing degrees of openness. For example, the Palm Beach County property appraiser's Web site tells you that Ann Coulter paid $1.8 million for her home in Palm Beach, but the Dallas County appraiser's Web site doesn't tell you how much Mavericks owner Mark Cuban paid for his palace in Big D. An estimated market value is available, but not the purchase price.

OK, Ann and Mark, you can see my house, too.

So the best government source isn't always a Web site. Sometimes you have to visit the county courthouse and look through property records in computers and books. Start out by looking for your county's property appraiser, tax assessor, recorder or clerk online. It helps to have patience (because most local governments have horribly designed Web sites), an up-to-date computer (because the sites like to throw Java applets at you), and a fast Internet connection (because the sites throw Java applets at you).

If you can't find the information you want, call the appropriate office and ask where you need to go to get it.

Visit Web sites that estimate home values
A new Web site called Zillow.com has grabbed a lot of attention, although it's not the first of its kind. The site lets you get estimates of home values by typing addresses into a box. On Zillow, an estimate is called a "Zestimate," and if the information about a home is incomplete or inaccurate, you can update the information and get a revised estimate.

Zillow is addictive because it's easy to navigate, and it provides maps and satellite photos that let you see the estimated values of your neighbors' homes, too. Take the aformentioned Mark Cuban: When this was written, Zillow estimated his estate to be worth $11.5 million, while a neighbor to the north has a home worth a relatively paltry $1.33 million.