As promised by Google during it’s keynote announcements at the Google I/O, just a bit over 36 hours ago, Google has made the factory images of it’s latest Android build available. These factory builds are currently available for only the Nexus 5 and the latest 2013 variant of Nexus 7 tablets. The factory images, as expected are in .tgz format and will require a full wipe of your device followed by you needing to manually flash them. If you have never flashed a factory image, you can read several guides that are available across the internet like this one, though we recommend you doing this with an expert to prevent bricking your phone.
You can access the two factory images right at the links given below:
Android L Developer preview for Nexus 5 can be downloaded from here
Android L Developer preview for nexus 7, 2013 version can be downloaded from here
While the factory builds are available only for Nexus 5 and the most recent version of Nexus 7, several people have noted that a fair few screenshots of Android L were indeed in 768 pixels fueling the rumor that Google will make Android L available for its older generation of devices such as the Nexus 4 and the previous generation Nexus 7. Meanwhile, HTC has become one of the first OEMs to publicly declare their support for Android L stating that both the HTC M7 and M8 will be getting the update within the period of 90 days since the day Google seeds the final version to them.
Here is a video showing off how to install these factory images on your Nexus 5 for those who may be interested: