Samir passes along a new travel metasearch site, Kayak.com which is similar in many ways to SideStep and Mobissimo with a clean, user-friendly interface.

You enter travel search criteria, it scours multiple travel providers, and collates the results.

It isn’t a silver bullet tool but it’s definitely one to add to the arsenal (and to add to my How to Get the Best Airfare Deals FAQ when I get around to updating it).

Like other similar sites, Kayak.com makes money on referral commissions for your purchases. Doesn’t bother me a whit, it’s a useful tool so well they should make something.

Their partner list isn’t as extensive as Mobissimo’s, they don’t seem to include consolidators like OneTravel for instance in their searches, but they include more search parameters like including multiple airports so Kayak.com’s added functionality could well generate lower priced results than competitors.

Free registration is required to use the site.

Update: Here’s an article on the service (thanks to Samir for this pointer as well). Executives of the service come from the major travel websites. They plan to add car rental searches to the air and hotel offerings on the site.

Some of the current and planned interface features include:

Users can adjust airline results by checking or un-checking airlines, and tweaking sliders for price or flight times. With hotels, users can refine by distance from a given location, by price or by star rating. The site has both Flash and HTML interfaces, which users can toggle between.

…

The company’s planned personalization features are just starting to appear in the beta test. In the airline search area, the main effect so far is that Kayak.com remembers previous searches and allows users to easily perform them again. In the hotel area, Kayak.com allows users to rate hotels and leave comments about them. Eventually, Hafner says, the company will introduce Amazon.com-like collaborative filtering, which would suggest to users that, for example, people who liked hotels they liked in San Francisco, also liked certain hotels in New York. The company also hopes to learn enough to distinguish between good suggestions for business travel versus good suggestions for personal travel.