There are three sites that people have recently emailed me about. I haven't had much time to explore them, but I thought I'd pass them on:
FlightStats: As far as I can figure, it's kind of a clearing house and rating system for airports and carriers. I have to log in to view a bunch of features, and I'm not inclined to register, so I can't see the whole site. They do have some cool looking widgets for the Google toolbar and your website, such as this:
Tripmates: "The interactive travel community that gets you connected before you depart and keeps you in touch while you're away." Hooray for websites which clearly articulate what they do! Friendster for traveling, from the looks of things, and appears to appeal mostly to the backpacking set. Lord knows that I don't want to travel with total strangers (I don't even like travelling with my friends and family), but looks useful for those who do.
TripTie: The most Web 2.0ish of these sites, and the most interesting looking. "TripTie is an online community of travelers, all devoted to planning and sharing their trips. Members plan and store their itineraries, then you take the best pieces of them and create your own." It looks like quite a deep application–great for the obsessive trip planners. I made a 'trip plan' (that's how they chunk their data), but I couldn't figure out how to share it with the world. Maybe I can't yet, as they're still in beta?