Tom's Hardware Guide has written a brief introduction to sampling audio:
Welcome to the next installment of Tom's Hardware Guide's do-it-yourself digital audio tutorial. The purpose of this article is to tell you all you need to know about sound sampling. The quintessential building block for most songs made in the last 15 years, there is nothing more ubiquitous than the sample. Almost every recent rock, hip hop, R&B, pop, and electronic music track now incorporates the use of samples. Wouldn't you like know how to unleash the potential of this powerful technique?