This isn't a pure AA dining promo, but AA dining is part of the AA "30 deals" (30th anniversary of AAdvantage) day 3 promo: Shop, Dine, Travel.
To earn 3000 bonus AA miles:
1. Go to the AA "30 deals" site (easy to find if you go to aa.com and just watch the rotating banner ads until the "30 years / 30 deals" one comes up, go "back" to day 3, enter your AAdvantage number and click Get Deal to register.
2. Spend $30 cumultaive on AA eShopping. That's the Shop part.
3. Spend $30 cumulative on AA dining. That's the Dine part.
4. Earn miles for a flight, parnter hotel stay, or partner car rental. That's the travel part.
All this needs to be completed in about 5 weeks.
In my case, I'm already AA dining more than that in a month anyway, so that part's "free". And I already happen to have two flights during this period, plus already was planning to do some BW stays with the bonus AA miles promo there, so either way that's "free". For me the only "work" will be figuring out something to actually want to buy on the AA eShoopping website!