Pico projector makers quelled rumors that the iphone 5 will have an onboard pico projector. The technology is not where it needs to be in terms of brightness, resolution and power consumption to be practical in a smart phone. Currently, Samsung and LG have smartphones on the market with pico projectors. The Samsung Beam is an Android based smartphone with a TI DLP projector capable of 6 lumens. The LG phone no longer shows the pico projector attachment on their product page.

Personally, I would rather have a separate brighter pico projector until the technology catches up. 6 lumens is not bright enough to be useful in anything other than complete darkness.

source: digitimes.com