M.M.
I took Salsa at the Society Hill Dance Academy in Philly but they also offer many different classes as well as private lessons. The instuctors are awesome as well as being in a beautiful part of town. http://www.societyhilldance.com/
My husband and I also took dance lessons through the community catelog listing, usually if you go to local school districts web sites there is a link for community education, most of which include some form of dance.
One other place I have seen lessons offered is through the YMCA.
Good luck!