Geert van der Cruijsen has created a tool that makes it easy for you to change the skin on your windows phone emulator. Its pretty cool. It allows you make your emulator look like one of the new Nokia Phones.
Keep in mind that it is beta.. use at your own risk 
Check it out here.
http://vdcruijsen.net/2011/12/windows-phone-7-emulator-skin-switcher-1-0-beta/