The FOC date for retailers is Monday, May 4. That means you need to let your comic shop know BEFORE THEN that you want a copy or you might miss out.
There will be some different covers you can choose from. The Francis Manapul cover has just been revealed.
The Manapul cover is actually Cover B. Series artist, Toni Infante, does the art for Cover A, which you've likely seen already.
Paolo Rivera also did the art for Cover C.
If you were a Kickstarter backer and pledge to receive a copy, you'll get a super-rare exclusive cover by Siya Oum. This one is limited to just 500 copies.
Again, the FOC is Monday, May 4. Let your comic shop know you want this added to your pull list before it sells out.