Hi Anne,
I agree with you; free dining promotions are the best! In all my years of visiting Walt Disney World, I've never qualified for a free dining offer but I'm hopeful that I will get the chance to enjoy one some time in the future.
We never know in advance when free dining offers will be extended. However, historically we see these promotions offered during periods of relatively low park attendance. Normally that means months when most American school children are in the classroom. Mid- to late-September, October, February...these all tend to be months when free dining offers are more likely. However, that trend could certainly change in 2013.
My best advice to you would be to follow the
Special Offers page at www.disneyworld.com closely. That's where this type of promotion is most likely to appear. It wouldn't hurt to enlist the help of a Disney-savvy travel agent too. He or she could help you look for promotions that apply to your desired dates of travel.
Meanwhile, I suggest you book your vacation now for 2013. If a free dining promotion is offered after you book your trip, just call to revise your reservation. New promotions will not be added automatically. You must call to request the change. Again, a travel agent can be very useful in this regard.
Good luck planning your trip. I'll keep my fingers crossed that a free dining promotion will become available during your desired travel dates.
Jill