I have been hearing from some of you re: reservations. 

Zulum is holding a block of rooms for us (Park/Helmling wedding) but only until the end of March.

As far as airfare, the rates I have seen lately have been slightly high.  I would wait about 3-2 months before the big day before booking.  I have a feeling that rates might drop.

Airlines that fly to Mexico:

from NYC area: United, Delta (with stop), JetBlue, AA

from LAX: United

More information on Tulum:

I found a great map that shows the hotels in relation to each other.

http://www.bill-in-tulsa.com/mapoftulum.html