The Windows Phone 7.8 update has been rolling out however you may have to have some patience before you will actually receive the notification to update your phone. It was originally thought that just Nokia’s Lumia lines of phones would be getting the update this week but that turned out not to be the case as other devices are being reported as getting the 7.8 update too.
If you don’t see the notification on your phone you can plug your phone into your PC running the Zune software and go into the setting and hit check for update. That may not guarantee you get the update early but usually that will work faster than getting the Windows Phone 7.8 update notification on the phone. The update procedure will look a lot like the Windows Phone Update Tango update where we installed Tango.