Delta SkyMiles American Express cardholders can receive 500 bonus miles
by registering for its SkyMiles Dining promotion
. (It's free to enroll.) Plus, spend $30 or more
(including tax and tip) at participating restaurants, bars, or clubs within 30 days of registering to get an additional 1,000 bonus miles
. That's the best deal we've seen for Delta SkyMiles, aside from opening a new credit card account, since last year. After the initial 30 days, eligible dining charges earn five miles per dollar. Bonus miles will appear in your account within four to six weeks. Deal ends March 31.