Follow this link, click the Register button, and enter your RR information to sign up.
Terms and Conditions
One additional credit per one-way will be issued, except Business Select. Business Select Customers will receive 2.25 credits for flights less than 750 miles and 3.0 credits for flights 750 miles or more. Member must register for this promotion between June 17, 2010 and July 14, 2010 to qualify, and registration must be completed prior to commencement of travel. Valid on new reservations only. Reservations must be booked between June 17, 2010 and July 14, 2010. Qualifying travel must be completed between June 17, 2010 and August 25, 2010 to or from St. Louis. Rapid Rewards account number must be entered at the time of booking. Members will receive one bonus credit per qualifying one-way flight. Travel on an Award or Companion Pass does not qualify for promotion. Bonus flight credits do not count toward A-List qualification. Rapid Rewards credit will post to your account within four days of completing travel. Changes made to the itinerary after purchase may eliminate qualification for this promotion. All Rapid Rewards rules and regulations apply.
Be forewarned, if this is like Airtran’s MKE promotion (as the terms make it seem), you will not get double credit for connections through St. Louis unless you book them as two separate reservations. It may make sense to do just that if getting the two bonus credits for connecting in STL is worth the extra hassle. St. Louis strikes me as an excellent place to connect with a nice central location for continental US flights and plenty of direct service to other SW cities.