Below are a series of tutorials that cover basic information on why and how to create organized 2D texture space (UVs) on polygon meshes. Enjoy.
Why Learn UV Mapping?
UV Basics 1: A Quick Overview of Tools Before Techniques
UV Basics 2: Getting Started with UV Mapping in Maya 2010
UV Basics 3
UV Basics Continues here with Texturing Basics
UV Mapping Hard Surface Models 1
UV Mapping Hard Surface Models 2
UV Mapping Hard Surface Models 3
UV Mapping Organic Forms 1
UV Mapping Organic Forms 2
UV Mapping Organic Forms 3
UV Mapping Organic Forms 4