Google may have already dropped the mention of beta from the Ingress Play Store listing, however it looks like the game still has a few weeks before the beta officially ends. Niantic Labs has announced that Ingress will exit beta on December 14, 2013. This date coincides with the conclusion of the 9-week, 39-city global event that is called Operation #13MAGNUS.
Niantic Labs is touting this as being the "biggest milestone since the introduction of Ingress." And as such, they are offering something special for those who have been playing the game. By dropping the invitation requirement, Niantic Labs is openly looking for new players. Or in this case, for new "agents." Whether you are coming in as a new agent, or have been playing, you now have the opportunity to earn "The Founder Medal."
This achievement will be given to all agents that manage to reach Level 5 before December 14th. Otherwise, along with The Founder Medal, Niantic Labs has also announced The Ingress Elite V challenge which kicks off today, November 4th. This one will run through the December 14th and is open for all agents. This one will be an effort to identify the five most elite agents from around the world.
That having been said, Ingress has been around since November 2012 and while it has been in an invitation-only status since then, those invites haven't been all that hard to come by. Needless to say, if you had wanted to get going with Ingress but were unable to find someone willing to share an invite -- that obstacle has been removed and you can head to the Play Store, download the app and get to playing.