It's hosted by a real estate company (no affiliation) but there is a link at the top right of their HOME PAGE to a live webcam with updates every few seconds. Also shows the current temp and (I assume) humidity.
Very high quality image and an instant weather check
Maybe it's just that the heat's getting to me, but I got a kick out of watching the cars go by! I guess I never saw a webcam with that fast a refresh rate. It's much more fun than watching the hikers on Mt. Washington's summit cam. The view's not as nice, though...
Just checked it again and it seems to have gone offline at 8pm. From the address of the realtor I'd say the view is looking east on Rte 112 in Lincoln and my best guess is that the domed peak in the view is Potash Knob. I could be wrong of course.