I'm a huge fan of TripIt and the organization it provides. Recently, a friend's flight was delayed due to a huge snowstorm, and she received her TripIt flight delay notification (via the app) nearly a half hour before she received a notification from the airline. She was able to quickly rebook a different flight before other passengers attempted to do the same thing, and the rest of her travel plans were unaffected. Both apps are available for download from TripIt's site.
Following the success of their popular iPhone app, travel site TripIt has released apps for both BlackBerry and Android phones. The apps are free, but require you to sign up for a free account on TripIt.com. The applications are an easy way to access your travel plans on the go (say, when you're in a cab from the airport and can't seem to remember the name of your hotel). The app also provides one-click access to call your airline, hotel, or other location directly from your itinerary if you have questions or problems.