$10 off each way on JetBlue using your Amex card

JetBlue and American Express right now are having a promotion that nets you $10 off a one-way fare when you book via this page at JetBlue.com using your Amex card.  The discounts are combinable, so you can get up to $20 off on a round-trip if both flights meet the rules of the promotion.

This offer is valid for flights between September 5, 2007 and October 31, 2007, excluding Friday and Sunday travel.  The offer expires on 8/31.