Do you consider yourself lucky? If so, you may want to go check your inbox right about now. For all you know, there might be a MAG beta invite waiting there for you as it seems the game has had enough internal testing and is ready to be tested by the gaming public.
Sony's started sending out invites for MAG's public beta enrollment. Note that getting this doesn't guarantee you a spot in the beta. The code included in the invite just nets you access to a closed application form.
These invites will be sent out by waves, so if you didn't get one yet there's still a chance for you to be invited in subsequent waves.