Emirates have had them on the 777's since 1998 at least.
Did a trip LHR to DBX, the views on the stand were interesting, the loading people and tug driver all centre stage and probably not aware of it, then the taxying and takeoff, after that no use at all, until the final approach at night, and again the interesting view of the lead-in lights and the rabbit.
They are a bit gimmicky at any other time, a vertical view from 39000 feet at night is much like the proverbial paint drying.
I read yesterday that the next shuttle, or is that todays shuttle will have a similar camera in the nose of the external fuel tank, its a one way trip for the camera, but should be interesting, try the NASA web site for details.