As rumored earlier today, Google has unveiled the a Samsung Galaxy S4 that actually runs on pure Android with an unlocked bootloader. The new Galaxy S4 will be available via Google Play Store as of June 26th with a price tag of US $649.
According to Google, the new Samsung Galaxy S4 will offer Nexus user experience and will work on both T-Mobile and AT&T networks in the USA with LTE support. In case you are wondering, it is a 16GB version and will, according to Google, recieve prompt system updates as they come out on other Nexus devices.
As noted, it will initially run on Android 4.2 Jelly Bean. It will be sold directly from the Play Store and, unfortunately, it will initially be available only in the USA.