For just $259, you could own the “World’s Smallest Color Wireless Camera” — measuring just 1″ x 1″, it can be concealed just about anywhere. It’s powered by a single 9V battery and runs for approx. 10 hours — transmitting all video to TV channel 59.

I’m sure the FBI the NSA or even MI6 have even smaller versions. However this is most likely the smallest color wireless camera readily available to consumers

[Source]
from techeblog