I read a very informative article on ZDNet tonight written by Matthew Miller.  Matthew was given a Windows Phone 7 device to use for a couple of weeks loaded with a "technical preview" (beta) version of the mobile OS.  Matthew gives us a very in depth look at a the Windows Phone 7 operating system including 7 videos and around 90 photos. 

Microsoft Windows Phone 7 technical preview: A definitive guide
http://www.zdnet.com/blog/cell-phones/microsoft-windows-phone-7-technical-preview-a-definitive-guide/4286?tag=mantle_skin;content

Windows Phone Blog
http://windowsteamblog.com/windows_phone/b/windowsphone/archive/2010/07/18/a-windows-phone-7-milestone.aspx