Emad Ibrahim is the creator of many Windows Phone applications, such as Envision, Notesly+, QuoteZen, and Picasa Viewer.
In this video, he talks about his Windows Phone experiences so far; the video is aimed at developers, so it does not do thorough job at demoing the apps (see related links section below for better demos). The video is part of the "An update from the Windows Phone developers" blog post. Might want to read that to understand the context for the video.
Envision is a basecamp site for Windows Phone. Video walk through is here