Just got an e-mail from Alamo offering Triple Rewards with several airline partners including WN.

Just provide your membership number for your preferred program when you make your reservation and earn triple rewards (miles or credits) on qualifying Alamo rentals. This special offer is available through June 15, 2009 on AIR MILES®, Alaska Airlines, American Airlines, Continental Airlines®, Delta Air Lines®, Hawaiian, Northwest, Southwest Airlines®, United and US Airways®.

Ts&Cs:
Earn 1.5 Rapid Rewards® credit per rental instead of the usual 0.5 when making a reservation using one of the Southwest offer links on this page. Offer valid in United States and Canada. A frequent flyer surcharge of $2.00 may apply. All Rapid Rewards program rules and regulations apply. Allow 6-8 weeks for credits to post to your account. Offer is subject to vehicle availability. Any changes to the reservation may disqualify member from promotion. Not combinable with other Alamo or Alamo-affiliated promotions.

Corp I.D. = 7013567
Valid = Now through 6/15/09
More Info