I've been playing with Tripit.com lately, it's a startup with a really clever but simple approach to travel planning. You don't even have to register, just forward the confirmation e-mails that you get from airlines, car rental agencies, Orbitz, Travelocity, Amtrak, Eurostar and other travel companies and websites to firstname.lastname@example.org. Tripit parses the e-mails, including attached PDFs, and builds an itinerary for you, complete with historical temperatures, maps, and links to information about your destinations from Wikipedia and other sites. For flights, Tripit adds links to check flight status and to check-in. Itineraries are editable and you can add notes. The first time you send an email to Tripit you get a reply with a link to verify your account. Verification is extremely simple, just enter your name and choose a password and you're all signed up. Now that's ease of use!
If you add your family and friends to Tripit they can share your itineraries and you'll get "Closeness Messages" from Tripit when you cross paths with friends, just like you do with Dopplr.
Tripit Has a lot of alternate ways to use and share your travel data including Atom feeds of your trips and alerts and a "Tripit To Me" email bot that responds to commands like "get trip"
There's also an iCalendar server. iCalendar is the protocol used by Apple's iCal but it's also an open standard and is supported by many applications including Google Calendar, Microsoft Works 2008 and Outlook 2007, Mozilla Sunbird/Lightning, Zimbra, and KDE KOrganizer. I found it very easy to add Tripit to both Outlook and Google Calendar. If you are using Outlook clicking on an iCalendar link in a web page or email adds it to your Outlook Calendar. With Google, it's Settings > Calendars > Add Calendar > Add by URL I was a little disappointed that iCalendar doesn't provide bidirectional synchronization, Tripit's iCalendar items in Outlook or Google Calendar are read-only, you have to to go back to Tripit to edit an itinerary, but changes do get pushed back to the copy in Outlook or Google.
Tripit is useful for travel research too. You can create scrapbooks of notes and links about places you'd like to visit using a TripClipper bookmarklet. When you're planning a trip you can include items from your scrapbook. The bookmarklet works in Opera Mini (and probably Opera Mobile and IE Mobile) too. I've added it to my Opera Mini Bookmarklets page which makes it easy to add bookmarlets to Mini. Another cool tool is Tripit's Trip Search which automates comparison shopping for fares and accommodations by submitting travel details to multiple online booking sites.
Tripit Mobile Ratings: Content: Usability:
WapReview Blog - Bookmarklets for Opera Mini