(MONEY Magazine) – It's not unusual to find strangers lurking in Janet and Peter Lessem's Manhattan brownstone, fingering the cutlery, peeking in the medicine cabinet, sleeping Goldilocks-style in the beds. But the Lessems aren't calling the police. They're holed up in the homes of those very same strangers, perhaps in Provence, Maui or New Orleans.

Why? Because both the Lessems and their squatters want to vacation in a fabulous locale—without spending thousands on a hotel. So instead they take part in a growing practice called home exchanging. Notes Janet Lessem, who has swapped houses more than two dozen times over the past decade: "I can stay in great places for weeks at a time—and it hardly costs anything."

As long as you don't mind strangers rattling your pans, or expect room service in the morning, you can see the world this way too. All you need to do is list your home on an exchange site for $50 or so a year. You e-mail the owners of houses you're interested in—or they e-mail you—and you cut a deal. Perhaps you exchange cars as well. Maybe you agree to take care of each other's pets or to pay for cleaning.

It's a lot like another practice that has been revolutionized by the Internet—dating. You start by checking out someone's house photo. If there's interest, you e-mail. And down the road...if you both decide things are going well...you switch houses. In fact, experts say, you're best off approaching a house swap with the same perseverance, care and skepticism that you'd apply to Yahoo personals or Match.com.

Search in the right place. The big house-swap sites—Home exchange.com, Homelink.org and Intervac.com—give you the most listings. But you may be better off with a smaller site that narrows the field and introduces you to people like you. Teachers, for example, are likely to find swappers with similar vacation dates at Teacher homeswap.com. The site Singleshomeexchange.com is good for apartments.

Sell yourself. Market your house like you'd market yourself, but be honest. "Frequent exchangers can spot an exaggeration a mile away," says Glenn London, director of the exchange site The Invented City. Still, focus on your best assets. You may not have the geographic desirability of the Lessems, with their Manhattan zip code, but your hometown likely has a lot going for it. Veteran swapper John Mensinger lives in Modesto, Calif., a small city that's not an obvious tourist destination. But by selling his town as being less than two hours from San Francisco and Napa Valley, 2½ hours from Yosemite, Monterey and Carmel and near historic gold mining towns, he's come up with seven swaps in seven years.

Be skeptical. As e-daters well know, JPEGs can hide a multitude of sins. Photos are not, for one, a good indicator of whether your host is a decent housekeeper. If you're uneasy, says Homeexchange.com founder Ed Kushins, get referrals. "You want to hear from people who've been in the house." It helps not to dwell too much on the tit-for-tat part of the equation, he adds. You're not going to find brand-new, California-style accommodations in the heart of Paris, but isn't that the point?

Be patient. Give yourself at least three months—and plenty of false starts—to find a swap. And if you're not getting serious bites, the problem may not be your house but the area you're trying to swap into. While France and England are home to lots of eager exchangers, Greece, Italy and the Caribbean in season are notoriously hard swaps to come by. The few homeowners who list in those areas can afford to be choosy. Finally, you may have exchanged dozens of e-mails, but seal the deal with a phone conversation. "There may be a language barrier," Lessem says. "But talking with a person is the only way you know that they're not a total flake."