Delta is offering a 25% bonus on transferred miles from American Express Membership Rewards.

 

Details

Dear Mr. Weekly Flyer,

Don’t wait to start your summer vacation. Enjoy an additional 25% mileage bonus when you transfer Membership Rewards points from American Express now through June 30, 2010. There’s no limit to the amount of points you may transfer.The extra 25% mileage bonus may even give you enough miles for Award Travel. And with our three-level Award Travel structure you can combine cabins, dates and mileage amounts to get the flights you want. Award levels start at 25,000, 40,000 and 60,000 miles. Plus, you’ll enjoy last seat availability at 40,000 and 60,000 miles. Why not register now and enjoy more miles and flexibility.

Registration

Registration is required here.

Airline Credit Cards

Bottom line

I wouldn’t transfer any American Express miles into my Delta account simply because SkyMiles are extremely hard to use to get value.  However if you are looking to top off an award or redeem miles for gift cerficates then this should add some value.