The Nokia Lumia 920 amber update which includes Microsoft's Windows Phone 8 GDR2 update will arrive over the air (OTA). There is a list on the Nokia website where you can see if it is available and if not, what the status is. My phone seems to be from Switzerland. The status on the Nokia website was set to ‘coming soon’, but I am really impatient when it comes to new software, so I downloaded the Nokia Software Updater for retail 3.0.8. Also known as NSU for retail. It is a >100mb .exe file and cannot be found (at the moment) on any official Nokia website. So I took mine from http://jkorondy.com/Lumia920 When you connect your phone and see a firmware which starts with a 3, then it contains GDR2+Amber.
After a reboot and logging in with my Microsoft account (live id) it tells me that there is a backup in the cloud which can be restored.
After another reboot (because of the Dutch language pack) it starts to download my apps from the store. But there are a few invalid apps. (I believe that it might be updates for apps without gdr2) so the apps fail to download and install. The problem (and solution) is described on this Windows Phone 7 tutorial website. So I had to manually uninstall all failing apps. It worked on my phone by going to the store and view the download app list and manually cancel the downloads.
Ow forgot to mention what the outcome was of my “Should I move to WP8” blog post. Well, I moved from Android 4.x to WP 8 and have all the required apps. None are missing. All apps have this nice native UI. Really like/recommend it!