Setting pdftitle and pdfauthor automatically in a LaTeX stylesheet

If you get compile errors, I’m guessing the problem is the @ character. You need to wrap your code in \makeatletter and \makeatother. Another possible problem is that you do this before you execute the \title and \author commands. A nice fix for this would be to use \AtBeginDocument, which would allow you to place this anywhere in your preamble. Note that you have to define the \title and \author information before \begin{document}.

\documentclass{article}
\usepackage[pdftex]{hyperref}

\makeatletter
\AtBeginDocument{
  \hypersetup{
    pdftitle = {\@title},
    pdfauthor = {\@author}
  }
}
\makeatother

\title{Test title}
\author{Sam Author}

\begin{document}
\maketitle
\end{document}

UPDATE: Putting the relevant parts in a style file named xxx.sty:

\NeedsTeXFormat{LaTeX2e}
\ProvidesPackage{xxx}
\RequirePackage{hyperref}

\makeatletter
\AtBeginDocument{
  \hypersetup{
    pdftitle = {\@title},
    pdfauthor = {\@author}
  }
}
\makeatother