Right now, the big thing about August's White Dwarf is that Lizardmen are revealed for Warhammer Fantasy. The one thing that no one is yet talking about, is that the rumors are true........
Black Legion: A Codex: Chaos Space Marine Supplement is in the August White Dwarf under digital releases.
Definitive Background for the Black Legion
Detailed Timeline of major historical battles and events
Additional rules (to lead your forces in a Black Crusade)
Reference for special rules and Wargear
While I dont have the date, I am sure it is in there and will follow last month's mid-month release. I just hope we are looking at a much faster hardcover release.