\documentclass{beamer}
\usetheme{Warsaw}
\title{Test-Presentation}
\author{Stefan Kottwitz}
\date{12.07.2008}
 
\newcommand*\oldmacro{}%
\let\oldmacro\insertshorttitle%
\renewcommand*\insertshorttitle{%
  \oldmacro\hfill%
  \insertframenumber\,/\,\inserttotalframenumber}
 
\begin{document}
 
\begin{frame}
  \titlepage
\end{frame}
 
\begin{frame}
  \frametitle{Inhaltsverzeichnis}\tableofcontents
\end{frame} 
 
\section{One}
\begin{frame}
  \frametitle{One}
  This is a presentation
  testing the split theme with frame number.
\end{frame}
\end{document}