welcome!
1: there's a setting to switch it inside settings, but that's a pain. There are plenty of programs out there that give you shortcuts to switching from landscape to portrait. it's a little heavy for what you're asking, but check out SPB Mobile Shell, which does a TON of cool stuff but also has a today screen button to switch orientation (doesn't it?)
2) Tsk. I think that with some video - especially streaming video -- that's just how WMP is going to display it, period. A bummer. You might check out Core Player (or TCPMP), it should give you more zooming options for video.