If you wish to see how your designs would look like on a mobile screen with very little overhead, I recommend you try LiveView. I’ve been using it to compare a mobile website with the original designs, and it’s working great for me.
LiveView takes a part of your screen and broadcasts it to connected devices over Wi-Fi. It’s ridiculously easy to set up and works like a charm.
Unfortunately, it’s exclusive to OSX and iOS, but if you know about an Android equivalent, I’d love to know!
Check out LiveView (Mac OSX/iOS)