Through Sept. 30, 2010, Delta SkyMiles American Express cardholders can earn double miles on all eligible purchases and triple miles when purchasing Delta, Delta Connection or Delta Shuttle flights and Delta Vacations packages. To be eligible to earn double or triple miles for credit card spend, however, you must redeem a minimum of 10,000 SkyMiles by Sept. 30, 2010. Registration in the Bounce Back promotion is required at http://www.deltabounceback.com

Bottom line: With this promotion, you have to spend some miles for the opportunity to earn more, which may or may not make sense depending on how much you are planning on spending to the card during the promotion. If you were planning on redeeming SkyMiles for an award ticket anyway, and already have a Delta SkyMiles American Express card, then be sure to take advantage of this offer. Double miles on all spending for the next three months can help to replace the miles spent. If you use a SkyMiles American Express card regularly but don’t have any upcoming travel plans, you may want to consider spending the minimum 10,000 miles at the SkyMiles Marketplace just to get double or triple miles through Sept. 30. While we normally don’t recommend redeeming miles for merchandise because the value per mile is low, you could, for example, redeem 10,100 miles for a box of Godiva Signature Truffles and then enjoy a box of chocolates plus the double or triple miles. Or you could redeem miles for a car rental, hotel stay, magazine subscriptions, donate miles to charity or use 10,000 miles to get a $100 discount off a Delta ticket with Pay with Miles.