Good old Jaxbot from Windows Phone Hacker has managed to get his hands on a pre-release version of the Windows Phone "Tango" emulator (build 8731, which is earlier than the shipping 8757).
In addition, he's gone an unlocked the whole thing making it available for others to download and use. But for those of us who don't want to bother they can just watch the above video walkthrough demonstrating the few changes that are present in "Tango" (most of the changes are under the hood). Things like voice-notes in MMS or the location-icon detailed earlier though are nice little changes.
All in all, not too much to get excited about but if you want the emulator, head to Windows Phone Hacker for more info and the download links.