The Malaga city bus line is called the EMT (Empresa Malagueña de Transportes). Below is its website (unfortunately only in Spanish):

http://www.emtmalaga.es/portal/page/p...

The No. 19 bus goes from the city center (stops at City Hall, Plaza de la Marina-across the AC Malaga Palacio Hotel, and Alameda Principal) to the airport about every half hour, starting at 6:25 H. to 23:30 H. From the airport the bus goes to Malaga starting from 7:00 H to 24:00 H. It takes about an hour to get to the airport.

The fare is one euro for 2008.

To look at the bus routes and schedules, push the Lineas y Horarios box at the top of the web page.