Windowsphonemedia.com has a forum that has sort of died down lately. But it would be cool to see it get busier.
It's basically a place where some of the old Backstage people went. We were all on the Windows Backstage forums months before Windows Phone launched. But once it launched, it wasn't really a "backstage" thing anymore. So Microsoft made a little farewell video and closed the Backstage forums. So we all looked for somewhere to go.
Though I imagine many of them are actually here on WPCentral now.
So to any Backstagers... I was "Winning Guy" there. Give me a shout!