Picoprojectors suck for most of the advertised uses as they're just not bright enough. They are about as good as those "convert your TV to a projector" sets, the difference is just that the projection area is smaller and they have no speakers.
Still, i might get one to mount it so that i can watch TV on the ceiling when lying in my bed. But i'll wait with that, i'm sure their prices will continue to plummet as they're not exactly flying off the shelves.