\documentclass[10pt,letterpaper]{article}

\usepackage{graphics}

\begin{document}

\begin{figure}
  %You need to include the image produced by MetaPost. If you call your 
  %MetaPost file example.mp then figure(1) produces example.1 and figure(2)
  %produces example.2, etc.
  \includegraphics{apple.1}
\end{figure}

\end{document}