You had to know those freebie WP7 devices for Microsoft employees would come with a few strings attached. We imagined the Redmond brain trust was aiming for some word-of-mouth popularization along with a boost in team morale and proactivity, but as it turns out, things are a little more codified than that. TechFlash has what it claims to be the internal memo announcing the free Windows Phone 7 handsets -- from mobile chief Andy Lees, who hasn'