Here is comprehensive website that dishes up all sorts of handy real-time flight information and delivers it in a variety of ways: on the site, through an RSS feed, and via cell phone—all for free. Search between destinations to see what flights are offered and if they have any available seats. No ticket price data here, but you will get historical on-time flight ratings.
FlightStats offers general airport delay information, airport maps with weather radar overlays, and real-time Google traffic information. Its flight tracker matches flights to gates and even lets you know when a plane has pushed away from its gate but has not yet taken off. If you forget to check FlightStats on your home computer, pick it up on your web-enabled cell phone at the terminal: http://mobile.flightstats.com.