Another Mobile World Congress in Barcelona has come and gone, and this one was clearly Microsoft’s show. “Windows Phone 7 Series” is nearly impossible to say out loud, but the OS itself meets the user interface bar set by Apple and Palm while tying together all of Microsoft’s consumer brands. I got hands on time with a prototype and was impressed, but if you want an early look yourself, you don’t need to be an analyst with access to high level Microsoft executives, you just need to scrape together $220 and buy a Zune HD. Zune lends WP7 both its user interface conventions and its PC software for media management, synchronization, and purchase. Microsoft still needs to convince developers to support the platform, but the company is relevant in mobile again for the first time in years.