As Disney are still to release details of their EMH for January 2013 it would seem that this is when it will come into effect.
Extended Disney park hours, known as Extra Magic Hours, offer a rare and unique opportunity to enjoy additional time in Walt Disney World parks—above and beyond the standard operating schedule—at no extra charge. This special perk is offered to Guests of select Walt Disney World Resort hotels, and Residents and Guests of Golden Oak.
Each day, one of the 4 Walt Disney World theme parks opens one hour early or remains open up to 2 hours after regular closing time. Additionally, Disney Water Parks offer Extra Magic Hours during select times of year.