Forget everything you know about Windows Mobile. Seriously, throw the whole OS concept in a garbage bin or incinerator or something. Microsoft has done what would have been unthinkable for the company just a few years ago: started from scratch. At least, that's how things look (and feel) with Windows Phone 7 Series. This really is a completely new OS -- and not just Microsoft's new OS, it's a new smartphone OS, like webOS new, like iPhone OS new. You haven't used an interface like this before (well, okay, if you've used a Zune HD then you've kind of used an interface like this). Still, 7 Series goes wider and deeper than the Zune by a longshot, and it's got some pretty intense ideas about how you're supposed to be interacting with a mobile device. We had a chance to go hands-on with the dev phone before today's announcement, and hear from some of the people behind the devices, and here's our takeaway. (And don't worry, we've got loads of pictures and video coming, so keep checking this post for the freshest updates).