That's right folks, the long awaited update 2.2 for Android OS is out but not for every phone. Sadly the update is just for the Nexus One phone so far and of course since this is a leak update you WILL have to install the update manually but there is another down side it will only work if you're using a non-rooted stock ERE27 system.
A post on XDA-Developers stated
"If you are on a completely stock ERD79 device (including stock recovery image), you can use the official ERE27 update (this is the same as the OTA update). Just download it, put it on the SD card named update.zip, launch recovery (power on with volume down held), press power and volume up when the warning triangle icon appears then select 'apply update.zip'. Sorted."
Here is the download link for the update
Source