Google's new Android Beta Program, which allows developers an easier way to download test releases of Android, is now live. The current program is for preview releases of Android N for select Nexus devices, and offers updates over-the-air.
Devices that you opt into the program will receive an over-the-air (OTA) update to the latest beta version of Android N. The updates that you'll receive as a part of this program are unstable pre-release versions, and may contain errors and defects that affect your device.
You may remain in the Android Beta Program beyond the N release to preview future Android N maintenance releases (MRs). If you choose to do so, you will automatically get an OTA update to pre-release versions of the MRs as they become available. At the end of the program, you will begin to receive regular public updates.
Right now, the Android Beta Program is available for the Nexus 6, Nexus 9, Nexus 5X, Nexus 6P, Nexus Player, and Pixel C.
Please note: this is not meant to be an easy way for normal people to get their hands on the latest Android features early. The Beta Program is target at developers, and is meant to make it easier for them to test their apps against an early version of the next version of Android. Things are guaranteed to break.