Look at the Subfloats section of http://en.wikibooks.org/wiki/LaTeX/Floats,_Figures_and_Captions.
\begin{figure}[htp]
\centering
\label{figur}\caption{equation...}
\subfloat[Subcaption 1]{\label{figur:1}\includegraphics[width=60mm]{explicit3185.eps}}
\subfloat[Subcaption 2]{\label{figur:2}\includegraphics[width=60mm]{explicit3183.eps}}
\\
\subfloat[Subcaption 3]{\label{figur:3}\includegraphics[width=60mm]{explicit1501.eps}}
\subfloat[Subcaption 4]{\label{figur:4}\includegraphics[width=60mm]{explicit23185.eps}}
\\
\subfloat[Subcaption 5]{\label{figur:5}\includegraphics[width=60mm]{explicit23183.eps}}
\subfloat[Subcaption 6]{\label{figur:6}\includegraphics[width=60mm]{explicit21501.eps}}
\end{figure}