To mark the corresponding author in the first page of the paper, you should use a small envelope. You can use the bbding package of LaTex, and use the command \inst{ (}\Envelope\inst{)} right after the name of the corresponding author, where is the number referring to different addresses or affiliations.
For example, Guojun Wang is the corresponding author and he is with the first affiliation, then it should be coded as follows:
\documentclass[runningheads,a4paper]{llncs}
…
\usepackage{bbding}
\pagestyle{empty}
\begin{document}
…
\author{ Guojun Wang \inst{1 (}\Envelope\inst{)} }
…
\end{document}