The company has its own , of course, which it demoed this week at Macworld Expo's Mobile Applications Showcase. TripIt's assembles customized itineraries for your trips. You forward confirmation e-mails for your flight, hotel, and car rental to TripIt, and the service parses those messages to assemble a master itinerary with all your travel information in one place. You can access that itinerary yourself and share it with others.

"In its simplest form, you get a really useful itinerary, with all the work done behind the scenes," TripIt's Peter Harrison said. "The 'wow' factor is you wind up not having to do anything."

TripIt's usefulness doesn't stop once it creates an itinerary. It also keeps you informed about any delays or changes to your schedule. In fact, when Harrison received an unplanned demonstration of this feature when showing off TripIt to me earlier this week--his planned flight back east the evening of our demo was canceled dues to the heavy snowfall, so his TripIt itinerary sported a bright red alert next to his flight time.

The iPhone version of TripIt is essentially a mobile extension of the Web service. You get a master itinerary of your flight, car, and hotel information complete with directions, weather conditions, gate information, and tappable contact info that you can carry with you on your iPhone or iPod touch. If there's a flight delay, TripIt will let you know with a mobile alert and helps you find alternate flight options.)

"It's the ultimate secret weapon," said Will Aldrich, TripIt's vice president of product. "Before the delay comes on up on the airport monitor, you're likely to be on the phone with customer care (booking another flight)."