\documentclass{beamer}

\author[thor,bar]{A. U. Thor\\and\\Foo Bar}
\title{Fooing a bar}

\begin{document}
  \begin{frame}
    \maketitle
  \end{frame}
  \begin{frame}
    \frametitle{This is a cool title}
    \framesubtitle{Not as cool, but still cool, this is a subtitle}
    Hello World!
  \end{frame}
\end{document}