Get the Android O beta download here
For those who can't wait for the final Android O release, Google had something else prepared. An updated version of Android O Developer Preview is now available for download.
If you've already installed the first Android O Dev Preview, then the OTA image should be automatically delivered to you in the next few days. Otherwise, you will have to register to participate in the Android O Beta Program so that you can flash the Android O Developer Preview 2 on your device. You can subscribe for the beta program here.
Keep in mind though that this Android O build will only work on the following devices:
One more thing that's worth mentioning is that Google has already released the factory images and OTA files for Android O Developer Preview 2, so you can go ahead and download them rather than wait for the update to arrive.