* Literate Programming and CWEB/NOWEB work great. ** Could use \scriptsize and/or \tiny and set the margins to 0--this is what I do:
\documentclass[10pt]{report}
\pagestyle{empty}
\usepackage{anysize}
\marginsize{0cm}{0cm}{0cm}{0cm}
\begin{document}
\tiny
\begin{verbatim}
BlahSourceCode
\end{verbatim}
\scriptsize
\begin{verbatim}
BlahSourceCode
\end{verbatim}
