Series 25 release will be staggered, with the starter decks releasing first, then the boosters 4 weeks later.
Here are the dates:
Theme Decks: Releases 05/11/12, legal for tournament play on 06/01/12
Boosters: Releases 06/08/12, legal for tournament play on 06/29/12.
The Reinforcement rule change (found here) will still remain legal on 05/11/12
If you have any questions, please post them here.