Southwest said today that it plans to continue an expansion of its international service with a code-share arrangement with Volaris, a two-year-old Mexican airline. The deal won't take place before 2010. Look for opportunities to connect for trips to Mexico from PHL with Southwest flights in, where else, the Southwest, perhaps in Houston, Phoenix or San Antonio. Or maybe from Florida or California. Read what we know as of today in the airline's news release. Southwest also is planning a similar coopertive service and marketing agreement with WestJet to Canada.