http://consumerist.com/2008/11/10/united-airlines-is-offering-20/

United Airlines is offering 20% off the 1st checked bag fee if you check-in online and pay the fee at United’s Web site (www.united.com) before January 31, 2009. They’ve also decided not to double the 2nd check bag fee as previously planned. [Cheapflights]

http://consumerist.com/2008/09/05/continental-has-added-a-15/

Continental has added a $15 charge on the first checked bag for some economy-class passengers, effective on tickets bought for travel on or after October 7. [Reuters] (Thanks, CMU_Bueller!)