I got this coupon for 10% off on Southwest.com. It's for last minute trips in April, but the fares were better than I thought.

PROMO CODE: SWAPRIL10
http://southwest.com/?src=EXTPDFRAPFS000000080327

The promo code entry is on the "Book Travel" page.

• Purchase must be made between March 27, 2008 and March 30, 2008 for travel April 01, 2008 through April 30, 2008.
• 10% discount valid for use at southwest.com off the total amount of roundtrip purchase before taxes and fees.
• The discount is only valid with the provided Promotion Code and is not combinable with other Promotion Codes or fares available exclusively through the web tool “DING!”.
• This promotion does not include Business Select, Business, or Senior Fares.
• Discount does not include taxes and fees.
• Roundtrip purchase required.
• Minimum seven day advance purchase required.
• Travel on ATA-only service is not eligible for this promotion.
• Changes made to the itinerary after purchase may eliminate qualifications for this promotion.
• Youth, Child, Infant, and Military Fares are not available for purchase at southwest.com.
• Reservations made through southwestvacations.com or swabiz.com are not eligible for this promotion.

Thank You!