I found this a nice push in the right direction and written for total beginners, plus its free to read and reasonably short:
Strobist: Lighting 101
There are also videos on youtube and other places that would probably be easier than reading for many people. I find long books on exposure to be too full of dry theory to really retain stuff well wheras the videos tend to show the application of the theory to teach it.
It is possible to make flash look totally natural or make it clearly not natural and yet still look good.
Going from natural light photography to artificial light photography (flashes, reflectors, lights, whatever) is like going from film photography to digital photography, there is honestly that much to learn and gain experience with using.
I am still fairly useless with artificial light.