The worldwide console launch of The Elder Scrolls Online: Tamriel Unlimited is on June 9th, and in preparation the console beta test has started! The beta test opened on Thursday, April 23rd, at 10AM EDT and ends on Monday, April 27th, at 10AM EDT. It's a limited, closed public beta. Invitations were sent to some - not all - of the people who signed up. However there's no NDA, so testers are welcome to stream their play and post screenshots.
If you were invited, start downloading now: ESOTU is an incredibly massive game, both in terms of sheer scope and the data required to bring you this truly enormous experience. At the moment, the client will exceed a 50GB Blu-ray disc which means there will also be a large day-one patch that is somewhere in the region of 15GB.
Don't forget, the PS4 version of The Elder Scrolls Online: Tamriel Unlimited is available for pre-order now on the North American PlayStation Store (Europe is soon to follow), and the Xbox One version will be available for pre-orders in the Xbox Marketplace in May. You may also pre-order both versions via select retailers.
For more information on the ESOTU Console Beta, see this post on the official site.