Android O is launching in preview state today, but you'll have to manually flash the OS to your test device to get a taste. The images and flashing instructions can be found here.
As a reminder, the Nexus 5X, 6P, Nexus Player, Pixel C, Pixel, and Pixel XL are the supported devices at this time. Google is not offering the O preview as part of the Android Beta Program for now (that will come later, of course), probably to discourage those who would try to daily drive an unfinished OS.
Google has said rather clearly that this early release is intended explicitly for developers and "not intended for daily or consumer use."Read More