Here’s your chance to pad your Dividend Miles account. From July 1 through Sept. 30, 2008, Dividend Miles members can earn up to 40,000 bonus miles with the Grand Slam promotion.

The more partners you use, the more bonus miles you’ll earn. You’ll earn a “hit” for each qualifying transaction with participating Dividend Miles partners, and for every fourth hit you’ll earn bonus miles in addition to the miles you would normally earn with the partner. You’ll earn 4,000 bonus miles for four hits, 8,000 for eight hits, 12,000 for 12, 16,000 for 16 and 20,000 bonus miles for 20 hits. For members who earn 24 hits, you’ll get a Grand Slam award for a total of 30,000 bonus miles; and if you really hit it out of the ballpark and earn 28 or more hits, you’ll earn a Hall of Fame award of 40,000 bonus miles.

To heat up the competition, the first 50 Dividend Miles members to earn a Grand Slam (24 hits) will get two upgrades to Gold Preferred Status — one for the registered member and one for a friend. You must register to earn the bonus miles and airline partners are not included in this promotion. Each “hit” must include a different partner, but you can also earn multiple hits for every second stay or rental with your favorite hotel and car partners. To learn more and to register, visit http://www.usairways.com/grandslam