How do air miles work?

How do air miles usually work with credit cards? Which cards would you recommend??

• Trying to pick out some good credit cards. Seems like all cards have different definitions of what exactly a mile is, what or how far a mile will actually get you, and restrictions on it. What's the basics and what're the better flier mile cards out there for someone who travels very little. & just while we're on the topic how about any good cards that have good benefits with low/no annual fees?

• Answer:

  Capitol One sucks. You can only redeem your points when you have reached 20,000 miles (dollars). Bank of America USAirways card is great, because they transfer your miles each time your balance is paid in full. American Express is the best. You can transfer anywhere you want, whenever you want.