you can make reservations for 180 days out, just like anyone else.(unless you have a package booked, in which case you can make reservations for 180 days , plus 10 (the lenagth of a room reservaton)
when (and if) they come out with "free" dining, just call and ask if you can change your room ony reservation to a free dining reservation. (note, there are seperate rooms set aside for different promotions, so having a "room only " reservation does NOT guarantee you a spot for the "free" dining promotion, at that particular resort.)
the reason I have the word "free" in quotes, is because the only way you get the
DDP (
disney dining plan) for free is if you pay rack rate for your room.
and they set aside X amount of rooms at each resort for these promotions. so, contrary to poplular belief, you could have a "room only" reservaton for a resort, say, French Quarter, and they might not have any rooms available for the free dining promotion for the same time period.
but, as per your question, you can make reservations 180 days out.