Factory images of the new OS version are already available to download and flash. The Final version is supported on the Nexus 5, Nexus 7 (2013 & 2012), Nexus 10 and the Nexus 4. If you have any of these Nexus devices, you should see the update now.
It is also worth noting that Android 5.0 factory images available only for the Wi-Fi versions of both Nexus 7 models as of now. Owners of 2012 and 2013 Nexus 7 devices with cellular connectivity will have to be a bit more patient.