These example night time photos from the Lumia 920 were apparently taken with an early prototype and are presented here. The full size versions aren't available for download because Damian and Nokia feel that their quality down at the pixel level won't be representative of that of the final device, with optimised noise reduction algorithms.
The reason these photos look so colourful, despite being taken in almost pitch black conditions, is down to the Lumia 920's party trick: optical stabilisation means that extremely long shutter times can be used (in these cases, up to half a second, I suspect) - good thing the model didn't move in that second shot though(!)....
Decent though these look, bear in mind that all companies release only the very best test photos to make their phone cameras look as good as possible. In the case of the other sample photos (e.g. here), there's no way of really proving what took them or the exact conditions - who knows what extra light sources were available?
The shots above were vouched for by Damian though. And I can't wait to do some low light test shots of my own when the Lumia 920 eventually appears.