I'm not sure if iDine is the same as this, but you'll get 3 miles per $1 at participating restaurants in your area.
http://aa.rewardsnetwork.com/
Go out for a nice dinner for two, spend $87, and you'll have 260 points posted within 3-4 days (from my experience). I go eat on Sunday, I receive an e-mail by Tuesday or Wednesday thanking me and showing the points earned.