As stated by T Moore, if you're on DP you won't get an over the air update to Cyan until MS and AT&T release it for the 920. They have released it for the 1520 and 1020, so I don't know why we're still waiting for it on the 920, but that's where we're at.
If you really want to get it today, you can install the Nokia Software Recovery Tool on a Windows 7 or 8 PC and then use that to update your phone. Note that AT&T phones no longer go back to Black/8.0 if you do this - it installs Cyan/8.1 directly. However, this will clear all the data on your phone. You can backup and restore your settings and apps, and you can take care of things like pictures, videos, music, messages, and contacts in various ways, but any apps (especially games) that don't have a backup mechanism will lose their data. It does give you a nice, clean install, though, and cleans up any junk that may be hanging in your phone's memory.