Nothing is ever for sure and things change from year to year but if you use last year as a comparison I am pretty confident people will be able to secure a room if they call reasonably soon.
Last year,
Free Dining was released for the general public on March 30th. Out of curiousity I tried booking all resorts at various times just to see how quickly the rooms disappeared.
I was able to book all resorts and room types up until Apr 22nd. So as you can see booking was not difficult at all. At that point some room types and resorts became unavailable with Pop Century, the Garden Wing room at CR and the standard room at WL disappearing first.
However, on June 11th, Disney extended the booking window to July 26th and at that point all resorts became available again.
Now, as Knox mentioned, there may be fewer rooms available this year, but given how the economy is still slow and Disney has been extending and adding Spring and Summer deals, I can't see all the rooms disappearing for a few days at least.
Of course, in 2008 things were much more hectic and things like the Standard room at WL and all rooms at Pop Century disappeared the first day, and some of the moderates disappeared two days after the deal started, but I have to believe that 2009 will be a better indicator than 2008.
Having said all this, I would still recommend booking the first day the deals become available. I would also recommend doing it online. You can easily wait 60 - 120 minutes on the phone if you call at 7:00AM with the hundreds of other people, where doing it online is painless as long as the servers don't crash.
)every other year it has been packed
We usually go around the same time every year. Id rather have it packed than the way that crowd was. Thats what I get for not fixing the dates on my camera
