Barra de São Miguel is about an hour south of Maceio by car. There are also several buses that make the trip.
It's all about the beach.
Praia das Conchas is a nice Portuguese owned pousada with a small pool . Near the center and about 100m from the beach. Rooms were about R$80 for a couple with small breakfast in March 2011. Website: http://conchas.no.comunidades.net/index.php. Phone: +55 82 3272-1685.
Praia do Gunga is a beautiful beach across the bay, about 20 minutes away by car. There is also a lookout point called Mirante do Gunga which offers a nice view of the beach.