• YELLOWPAGES.travel: Searches up to 12 travel Web sites, including Orbitz, Kayak, Expedia and SideStep. Users click on each site's logo at the top of the page for the results. SearchBoth.com, a subsidiary of YELLOWPAGES.travel, allows users to search two travel sites at the same time and places the results from the sites on a split screen.

• ProfessionalTravelGuide.com: Offers reviews of hotels and restaurants from professionals — journalists and expert reviewers from the travel industry — including insider tips and specific, detailed information about more than 159,000 hotels. These reviews are more like what you would find in a guidebook than in an anecdotal consumer review. Also has a customized guide for users who are traveling to several cities.

• yapta.com: Stands for Your Amazing Personal Travel Assistant. Enables travelers to tag flights from several airlines, including American, United, Delta and Continental, and alerts them when the fare drops. But unlike farecast.com, which predicts whether prices are rising or dropping, yapta can continue tracking prices even after you purchase the ticket. If you booked directly with the airline and the price drops below what you paid, you may be eligible for a refund or credit from the airline. (Other rules may apply — for example, some airlines charge a rebooking fee to capture the travel credit, so check the details.)

• Orbitz.com: Offers a new social networking component — OrbitzTLC Traveler Update — with real-time updates from travelers about security wait times, traffic and parking, taxis, etc. at more than 40 airports. Travelers can post the information on the Web site or send a text message. Orbitz encourages people to send information by giving out perks to people who send in tips and updates, such as a free pair of airline tickets.

• BestTripChoices.com: Matches travel personalities with best destinations. Travelers take a test and are classified into one of six travel personalities, ranging from "Venturers," people who are extreme risk takers, to "Authentics," people who want a relaxing, lazy vacation. The site recommends travel destinations based on the results. The destinations have been rated by travelers with similar personalities who have visited those places.