Airlines Informative - Must Read for all air travelers-Rule 240
If your flight is delayed for other than weather problems or reasons totally out of their control, you have rights under each airlines Rule 240 for compensation. You are eligible for free meal vouchers, hotel accommodations, phone calls, and other amenities. They may have to book you on a substitute flight on another airline. Most agents don't know about this rule but all US airlines have it in their contract of carriage. When you purchase a ticket you also agree to abide to their contract. Well, so do they.
For more information go to http://www.mytravelrights.com/travellaw.cfm?ai=3
(Why TWA is on the list is a mystery as they were acquired by American Airlines in late 2001)