1,000 Free AA or US Miles for Dining Sign-up
As I've written about before, dining for miles programs are free, easy ways to accrue miles. The best part about these programs is that once your credit/debit card is linked, you automatically get miles posted to your accounts. For example, I went to lunch recently with no idea that the restaurant was a participant in the US Airways Dining Club. About a week later, I received an email explaining I earned 72 miles (I would have gotten 120 miles if I was a VIP member, but I haven't gotten around to completing enough dines yet, though I should just buy 9 sodas as separate transactions from a participating restaurant).
Miles falling from the sky:
If you haven't yet signed up for a program, consider 1,000 miles for American Airlines or 1,000 for US Airways dining. Each require nominal effort to get the bonuses, like spending $25 on a meal and writing a review (twice).