Hang tight. It's coming
Windows Phone 7.8 upgrades appear on Nokia's servers for all eligible Lumias
Edit.
Seems it is already here
http://wmpoweruser.com/windows-phone-7-8-update-now-being-pushed-out-to-the-nokia-lumia-800/
Windows Phone 7.8 upgrades appear on Nokia's servers for all eligible Lumias
Edit.
Seems it is already here
http://wmpoweruser.com/windows-phone-7-8-update-now-being-pushed-out-to-the-nokia-lumia-800/