Go download the emulator images here -

http://www.microsoft.com/downloads/details.aspx?FamilyID=3D6F581E-C093-4B15-AB0C-A2CE5BFFDB47&displaylang=en

Peter Foot,   beat me to it,  showing off some of the new screen resolutions -

http://inthehand.com/blogs/peterfoot/archive/2008/04/02/new-windows-mobile-6-1-screen-resolutions.aspx

The impressive one to have a look at is - 480x800 !