I'll keep the status of H1Z1 updated in this thread.
On Steam: Yep
Early access: Available
Release date: Unknown
The early access will cost you $20, and if you wait till the game is officially released it'll cost you nothing, because it's a free 2 play game!
Keep in mind that we dont know the release date, it could take a while before it's released...
Once the game is in early access, a wiki will be added and the section will be expanded.