With a hurricane moving uncertainly toward the East Coast, anyone planning to travel through potentially affected airports through the holiday weekend should make sure to check on flights and possible delays and cancellations.
Continental, always Johnny-on-the-spot in terms of getting information to the public in a timely manner, says it's waiving penalty fees and fare difference charges for anyone traveling through certain airports through Saturday who changes flights (with new travel to commence by Sept. 19). Here's the Continental notice to customers, with the list of affected airports.
Other airlines will be making similar announcements soon. Note that Continental is waiving not just the change fees but any fare differences, meaning they won't charge you extra to rebook, even if the new fare is different. All airlines might not offer the same thing, so check carefully.
UPDATE: Delta, for example, just announced its hurricane-change policy -- and Delta is charging the difference between the old fare and a new one for anyone who changes plans. Sez Delta (italics are mine):
"Flight delays are possible Sept. 3-4 as a result of Hurricane Earl, and Delta may proactively reduce flight schedules to minimize delays. ... Travel for changed itineraries must begin by Sept. 11, 2010, and changes to origin and destination may result in a fare increase. Any fare difference between the original ticket and the new ticket will be collected at the time of rebooking. Customers whose flights are canceled may request refunds."