What is selective breeding and how does it different from "just breeding"? What is the difference between inbreeding and line breeding? What's an "outcross"?Well, here are articles that explain just that!
Selective Breeding - This article explains the difference between breeding and selective breeding.
Inbreeding - This article tells you what inbreeding really is and it's different levels. The article is very good reading material for breeders of not only mice, but also breeders of other rodents!
Strain Breeding - This article deals with the more moderate method of inbreeding, the strainbreeding.