We stayed at Iberostar Tucan in September 2008 for a few days. Good food, so-so resort otherwise. We dove ceynotes with Scuba Playa in PDC ( Diving Playa del Carmen - Scuba Playa Mexico - Dive Shop ) - pretty nice operators, very reasonable prices. Tankha Divers is another operator next door (Calle 10 in PDC). Unfortunately the winds were high during our stay there (which seems to happen pretty often in PDC) and the port was closed the whole time.
I clicked on the link above and McAfee warned me of two trojans that the link tried to load. Be cautious.
Rick