Behold! Windows Phone 7. Someone wasn't quite careful enough with his last minute update of this MWC signage and a passerby managed to snap this first glimpse of the WP7 interface, featuring bold, rectangular icons and Xbox integration.
This shot seems to confirm, to some extent, the bit of the last significant batch of rumors that promised tight Xbox integration. It also shows off the simplistic, geometric start page, including big, square icons for phone calls, messages, Twitter, and Facebook and a large band for accessing your pictures.