To celebrate the newly-introduced American Express Delta SkyMiles Credit Card benefit – a free checked bag on all Delta flights – American Express and Delta Air Lines are launching a Twitter-only promotion today, giving away 100,000 Delta SkyMiles!

It's easy to enter: follow @americanexpress on Twitter and tell them what you would pack in the extra space in your free checked bag. Simply tweet, “I entered to win 100,000 miles from @americanexpress and @delta. I'd pack [insert item here] in my #1stbagfree! http://srm.vitrue.com/x8E”

For more info/entry details, followers can check out http://srm.vitrue.com/x8E and keep an eye on the hashtag #1stbagfree.