The reason for the difference in image quality is that there is at huge difference in the amount of light in the two situations.
The difference is much bigger than what we experience because our eyes are able to compensate. And eventhough the camera is able to adjust in ways similar to our eyes it is not as succesfull. This is always the case in photography. Usually the first thing you give up in order to compensate is the sharpness in the depth (when the hole to take in light is expanded). The next thing to go is the general sharpness (when the grainsize on the film or reciever is increased). After that there is only the light level to lower.
Besides that the lenses on small cameras, such as in iPods, are tiny compared "real" cameras. And there are reasons why real cameras still feature lenses of that size. Those reasons become more evident in difficult conditions.
That's why but it's not going to improve your indoor iamges, I guess.