If you are interested in art and photography, we suggest you to check two addresses that provide good courses in Palermo:
Palermo foto, an excelent photography school, offers courses in Palermo all year round and in the island of Linosa in August
Contact Giuseppe: http://giuseppesinatra.tumblr.com/
For those interested in drawing/painting, we suggest an address that some of our clients tried and reccommended us...
Mialo art: http://www.mialoart.com/corsi.html