The idea is to use the \label, \ref mechanism, but defining a command to enclose the string produced by \ref inside a shaded ball like those used by beamer:
\documentclass{beamer}
\usetheme{Warsaw}
\usepackage{tikz}
\newcommand\ballref[1]{%
\tikz \node[circle, shade,ball color=structure.fg,inner sep=0pt,%
text width=8pt,font=\tiny,align=center] {\color{white}\ref{#1}};
}
\begin{document}
\begin{frame}
\begin{enumerate}
\item ... %Step 1
\item\label{ite:second} ... %Step 2
\item ... Go back to Step~\ballref{ite:second}
\end{enumerate}
\end{frame}
\end{document}

Since the french option for babel makes ; an active charcater, extra precuations will have to be taken:
\documentclass{beamer}
\usetheme{Warsaw}
\usepackage[french]{babel}
\usepackage{tikz}
\newcommand\ballref[1]{%
\shorthandoff{;}\tikz \node[circle, shade,ball color=structure.fg,inner sep=0pt,%
text width=8pt,font=\tiny,align=center] {\color{white}\ref{#1}};
\shorthandon{;}
}
\begin{document}
\begin{frame}
\begin{block}{title}
\begin{enumerate}
\item ... %Step 1
\item\label{ite:second} ... %Step 2
\item ... Go back to Step~\ballref{ite:second}
\end{enumerate}
\end{block}
\end{frame}
\end{document}
beamer? And you just want to duplicate the numbered item in the "reference"? – Werner Aug 20 '12 at 23:23beamer, and the\enumerateis actually inside ablockenvironment, that is why it is in blue... – SoftTimur Aug 20 '12 at 23:25