\begin{figure}[p]
\begin{leftfullpage}
<left side figure>
\end{leftfullpage}
\end{figure}
\begin{figure}[p]
\begin{fullpage}
<right side figure>
\end{fullpage}
\end{figure}
The construction has no effect on documents with class option
oneside (twoside is the default for
book class).
A special case of this requirement places the caption for a float on
the next page. (This is useful if you have a float that “only just”
fits the page.) You can (with a certain amount of twiddling) make
this work with dpfloat, but the fltpage package is
specially designed for the job:
\documentclass[twoside]{article}
\usepackage[leftFloats]{fltpage}
\begin{document}
...
\begin{FPfigure}
\includegraphics{my-huge-figure}
\caption{Whew! That was a big one!}
\end{FPfigure}
...
\end{document}
That example should produce a caption
Figure n (facing page): Whew! …(Note, however, that the package is an old one, and declares itself to be a beta release. I seems to work, but…)
This question on the Web: http://www.tex.ac.uk/cgi-bin/texfaq2html?label=dpfloat