Hasbro Pulse has sent out emails to those that preordered their Exclusive The Black Series 6-Inch Darth Vader (Revenge of the Jedi) Set, stating it is getting ready to ship out. Their product page shows a approximate release date of 6/8.
Preorders for this set was first offered to attendees at Star Wars Celebration and then to everyone else on April 11th.
If you are in need you can still place a preorder at this link.