The Fine-tuning argument attempts to claim that the physical, empirical scientific finding known as "Fine Tuning" indicates that there is a god. Fine-Tuning is, roughly, the observation that the laws of physics are such that changing the constants, even by a little bit, will result in a totally different universe, not fit for life. It is a Teleological Argument (specifically, it is a form of the Anthropic Argument), and is treated as such under that heading (go there!). The following deals with it more broadly.