Android 2.2 Froyo the operating system from Google has made a couple achievement. The first achievement is releasing their final Froyo update to Nexus One users and the second is Google open sourced the latest version.
Actually Nexus One is already running Android 2.2, but it seems the official Android 2.2. For all of Nexus One users who want to update or maybe just want to make sure for its availability, you can updates it directly from your cellphones go to settings > About phone > System Updates. Some people said that the update is not available for them yet. This is a gradual process and the update itself may different with the other places.
Google open sourced the code of Android 2.2 Froyo to everyone else. It allows everybody to run this version to non Nexus One cellphone without any permission to Google. This step helps Google to proceed their product’s expansion.
This is for everybody who runs FRF50 firmware, you could also download the update of Android 2.2 manually here.