Google has uploaded the Android 8.0 Oreo system images.
For those that want to be on the bleeding edge, the Android 8.0 Oreo system images are now available. Google has the images for last year's Pixel phones, the Nexus 6P and 5X, the Nexus Player and the Pixel C. Manually updating a device requires a few tools and a bit of time, but it's an easy process overall. There are carrier-specific images for the Pixel phones, so make sure you download the right one for your device.
For users that were on the Developer Preview, you should be receiving two Over the Air (OTA) updates to the stable version of Oreo. Depending on the device and version of the developer preview you're on, the first file should only be between 12MB and 50MB. The secondary update file clocks in at 900MB, so you'll want to be on WiFi for that one.