Well they've got May's schedule up, so in early April I would assume June's schedule should be up. Maybe even sooner. Keep checking.
As for crowds, it will be different this year because of the Toy Story (Midway) Mania opening. The first week of June will be low crowds, but after that, expect large crowds. The second week is full of grad nights and the third week lots of schools are out. Add on top of that, a huge new attraction opening somewhere around there and (if you look at what Nemo did this past summer) it will be crowded a lot of the month.