The derivation of MAGDALENA from the place-name Magdala is generally agreed. In the internet you can find still another explanation:
Mary Magdalen was so called either from Magdala near Tiberias, on the west shore of Galilee, or possibly from a Talmudic expression meaning "curling women's hair," which the Talmud explains as of an adulteress.
http://www.stjoanhershey.org/saint2.htm
Can anybody confirm this? A friend I asked said he found the word "migdelet" for a "hairdresser" in a dictionary. I can't find this word in my dictionary (Even-Shoshan), though. But then again: Maria Magdalene *is* the patron of hairdressers …