DALLAS - It's Southwest Airlines' birthday, but YOU get the gift! In celebration of the airline's 38th birthday, Southwest announced today special DING! fares as low as $38 one-way in select markets. These fares are customized for DING! subscribers and will only be available from 9:00 am to 9:00 pm CDT on June 18, 2009. In order to have your cake and eat it too, download DING! here.DING! is Southwest Airlines' downloadable desktop application that delivers discounted fares to a variety of Southwest Airlines destinations. The following are examples of city pairs included in this special $38 one-way fare offer (see Fare Rules below):-- Between New York LaGuardia and Baltimore/Washington for travel July 7 through August 31, 2009-- Between Los Angeles and the Bay Area (San Francisco, Oakland, and San Jose) for travel July 7 through August 31, 2009-- Between Philadelphia and Pittsburgh for travel July 7 through August 31, 2009FARE RULESThe fares are available for purchase through the DING! application only. Travel dates for DING! fares other than those listed above will vary and are included in the specific DING! offers. Fares are available one-way. Seats are limited. Fares do not include a federal segment tax of $3.60 per takeoff and landing. Fares do not include airport-assessed passenger facility charges (PFC) of up to $9.00 and U.S. government-imposed September 11th Security Fee of up to $5.00 one-way. Fares are subject to change until ticketed. Tickets are nonrefundable but may be applied toward the purchase of future travel on Southwest Airlines. Fares are valid on Southwest-operated published, scheduled service only and are not available through the Group Desk. Any change in itinerary may result in an increase in fare.