This style file is intended as an easy-to-use and easy-to-modify replacement for the existing uwthesis class. Instead of implementing an entire class (which involves an ugly mess of TeX internals), this style file builds on top of the excellent multi-purpose memoir class.
You can download the most recent version of this package as a zip file or tarball. Simply unpack it, and place the uwthesis.sty file in the same directory as your base .tex file.
To use the memoir class and import the uwthesis code, the top of your .tex file should look like this:
\documentclass[oneside, letterpaper, 12pt]{memoir}
\usepackage{uwthesis}
By simply importing the package, you'll get the right margins, spacing, etc. as required by UW--Madison. The package also provides commands to set all the relevant info (author name, defense date, etc.) and to generate the title/committee page, copyright page, and UMI abstract. The example.tex file provides a complete look at how to interact with the package.
If you want to change how anything looks, simply modify the uwthesis.sty file, which is made up of normal user-level LaTeX commands. It might be worth checking the documentation for the memoir class if you want to do something fancy; its scope is encyclopedic and the class provides nice interfaces for many of the changes you're likely to want to make.
Check the Examples page on the Wiki to see how others have fit this package into real projects.