Low-fare airline JetBlue has begun a frequent-flier program called TrueBlue. It offers points instead of miles, based on flight length. A round-trip cross-country flight, such as between Long Beach and Dulles in suburban Washington, is 12 points. It takes 100 points to earn a free round trip. The points expire after a year. Through Dec. 31, fliers who book through www.jetblue.com earn double points, enabling them to almost--but not quite--earn a free flight with four coast-to-coast round trips.