TripIt exists to make it easy to manage one or more travel itineraries, and to share those itineraries with other people (who can be passive viewers, or active collaborators).
Signing up is easy, requiring the minimum of personal information. Once you've registered and activated your account you can start adding to your trip itineraries. It is possible to do this the tedious, manual way, by typing in the details of you trip -- flights, car hire, accommodation bookings, and so on.
However, TripIt has an ace up its sleeve.
By forwarding the confirmation e-mails that you receive from the airline, travel agent, car rental company, and so on, to a special address @tripit.com from the e-mail address you signed up with, TripIt's systems will parse out the relevant details and import them as itinerary items in to your schedule. You can then amend them as necessary. This makes adding details a breeze.
As well as details for flights, accommodation, and car rental you can also add (Google) maps to your itinerary, either as simple maps, or as directions, and notes.
The collaboration features are simple but effective. Enter the e-mail address of someone you want to share the trip details with, and choose whether you want them to be able to view the itinerary, or to be able to add items to it too. They receive an e-mail with a custom URL allowing them to view/edit the trip details as necessary. These invitations can be managed by the original trip owner, and rescinded as necessary. Collaborators can add notes and comments to the itinerary, amend existing events, and add new ones.
For me this feature alone makes TripIt worthwhile. I no longer need to leave my mother detailed information about my travels around the world (she's a mother, of course she worries). I can just invite her to view the trip details.
TripIt's able to include other pertinent information in your itinerary that it gleans from the Internet. For example, for flights where it can determine the aircraft type it includes links to the relevant pages on SeatGuru, direct online check-in links, options to check the flight status, a brief display of the weather forecast for the destination, and so forth.
Other useful features include a "TripThis" bookmarklet which can be used to grab URLs of interesting pages and automatically add them to the itinerary, a "Travel Guide" for your destination, containing information culled from sites such as Wikipedia and Flickr, and growing support for "Friends" -- not a feature I've used, but they describe as:
... which enables you to connect with other TripIt users. Once connected, you can view an online calendar of each other's travel plans so you can keep track of traveling friends or business colleagues. This is the first of many tools that will make TripIt even more useful to organizing your travel...and organizing your friends too.
and TripSearch -- again, not something I've used yet, but it aims to make it easier to find and book flights, hotels, and so forth.
TripIt still has a few issues.
- It's still quite US-centric. For example, when it imports flight details and displays them on the itinerary it includes the appropriate contact number for the airline. But this is the always the US contact number, rather than the local one.
- There's no support for timezones yet -- although this isn't as big a problem as I'd expected.
- While there's a calendar view of the trip available via the website it's not possible to export this (say as iCal format) in to other applications (at least not that I've seen).
However, feedback that I've submitted to the developers has been responded to promptly, and I've seen features that I've suggested appear on the site quite rapidly, so it's entirely possible that these issues will be addressed soon.
Despite these few shortcomings TripIt has proved to be very useful, both in allowing me to easily organise my travel details, and in making it very easy to share these with other people. It also makes it simple to print out a detailed itinerary that contains all the relevant information, which is much nicer than carrying around print outs of half a dozen different confirmation e-mails which all have their information in different formats.
TripIt's service is free, and they are still in invitation-only beta mode. I have two invites left, and the first two people to request an invite in the comments can have them -- just leave your e-mail address.
Update: shortly after posting this I received an e-mail from TripIt with another 30 invites. So don't be shy in asking if you think it might be useful.