A reliable and great source for Windows Phone related news; WPCentral, yesterday posted three AT&T Lumia 920 training videos along with the news that AT&T in the US has a 6 month exclusive with Nokia regarding sales of the Lumia 920.
The videos give a very good impression of the Lumia 920, and I am reposting the first of them below:
The original article, with two more videos and some more details, can be found here.