You can apply now for a chance to get into the Evolve closed alpha testing session running from October 31 to November 2. The process is simple.
Step 1: Go here.
Step 2: fill in the bits and use this when it asks for a "17-character code" - 71687-90535-46031
This won't guarantee you access to the four-on-one humans vs. monster shooter as there's limited space, but it's worth a shot. You never know, y'know?
I played this for a couple of hours for the first time at Gamescom, and I'll say that it's more fun than it appears in promotional materials. The levels are big enough to hide as the monster, which I found myself doing more than expected. I ended the round as a fully leveled up monster, hiding across a land bridge and flaming anyone foolish enough to charge across.
If you get in, my advice is: always kill the medic.