ARMA 3's ALPHA release date was announced today:
CLICK ME - BIS FORUMS
To sum it up, you have to pay-to-play the ALPHA version. But before anyone flips, it's a pretty sweet deal. Basically if you pay now, you'll not only get access to the ALPHA, but also the BETA and the full game release. That's a rock'n deal.
There is also a "ALPHA Lite" version which is free, but it appears to be invitational only, meaning someone who has a full version of the ALPHA can invite you.
Anyway, BIS has a lot of different deals going on with this ALPHA release at the moment. The major things (game, editor, multiplayer, etc...) are available in all the versions. Make sure you check out the official website for more details and which package is best for you:
CLICK ME - ARMA 3 WEBSITE
Check out the "Play" link in the top right for all the package deals and the computer specs. needed to run the game. Also, a lot of new screen shots have been released, make sure you check them out as well.
See you on the battlefield!