The Dance FX Studios in Mesa are a strictly social dance studio (no competitions or showcases). They encourage their students and AZ residents to come out and learn how to become confident social dancers on a crowded floor with live music.
They host parties every month or so and feature local bands of all genres including Salsa, Swing, Argentine Tango each time. Check them out at www.dancefxstudios.com. Click on the Dance Events picture on the right for an Event calendar.
I have heard good things about Dance FX, give them a try.