I was going to book in April 2003 at the end of the month. My TA told me to wait until May (2nd I think to be exact), because it was Disney month. So we did. We booked the 01/10/04 Eastern 7-day Cruise and had our choice of rooms so room selection was fine. We got 6088.
As little perks for Disney month we received $100.00 shipboard credit, 3 lanyards (one for each of us) which are nicer than the ones you can purchase onboard, a mickey visor, minnie visor and Capt. Mickey ears hat (for DS6), 3 trading pins and I think that's it. All the stuff came with the docs from TA's office some time in December. She said it was from Disney so it wasn't a TA thing or promotion.
I will check with my TA to see if they are doing it again this year. I would check with yours as well. It was cute and fun and helped get us excited for the trip. Not that we needed more help.