So much for leveling a Legacy Raiding toon.
Check your Battle.net account. And, it goes without saying, be very, very aware of scams. This happened with Warlords. I got a legitimate invitation from Blizzard, followed by 4 invitations from nefarious email addresses. If you've been invited, you will be able to activate Legion in your Battle.net account screen. Send phishing emails to "Hacks (@) Blizzard.com". I've set up a forum thread for those of you who get into the beta.
Here we go.