Yup. Specifically, it is the AAdvantage Citi Card that has the 50k mile bonus right now (there is also an AAdvantage Barclays card, which kinda sucks). I think CosmicMoose dropped a zero as the terms state that you have to spend $3000 in the first 3 months to get the bonus. However, this might not be too difficult if you churn your monthly expenses through the credit card, as Booger stated (just make sure you pay it off at the end of the month, because the APR is pretty high).
Based on a similar discussion in another thread, I am in the process of cancelling my Barclays AAdvantage card (had it since it was a USAirways Mastercard) and opening a Citi account, just to get the bonus miles. When we flew back from Jamaica in early July, I was waiting for the flight attendants to hand out the AA Mastercard application at the end of the flight. When they did, I was disappointed to find out it was for the Barclays card and the bonus was only 25,000 miles. Anyway, the application for the Citi AAdvantage card is pretty easy to find online.