The zref package provides \zsavepos{<label>} using the savepos module
\usepackage[savepos]{zref}% http://ctan.org/pkg/zref
This allows one to place a regular \label-style label, this time using \zsavepos{<label>} and retrieve the (x,y) coordinates using \zposx{<label>} and \zposy{<label>}. Here is a minimal example:
\documentclass{article}
\usepackage[savepos]{zref}% http://ctan.org/pkg/zref
\begin{document}
Lorem ipsum dolor sit amet, consectetur adipiscing elit. Fusce rhoncus,
mi in interdum dignissim, urna purus rutrum est, vel sodales elit mi ornare
tortor. Praesent malesuada pulvinar nulla. Integer mattis tempus mi vel
accumsan. Maecenas commodo, ligula dictum interdum sollicitudin, elit justo
eleifend velit, at molestie ligula turpis vel risus. Sed consequat ornare
pellentesque. Curabitur congue sollicitudin semper. \zsavepos{mark1}Nunc ac mi semper nibh
placerat euismod sed sit amet nibh. Nulla neque magna, vestibulum at molestie
ac, condimentum et tortor. Nunc et turpis congue augue dapibus pulvinar.
Phasellus sagittis ipsum eget mauris congue ac condimentum tellus porttitor.
Pellentesque habitant morbi tristique senectus et netus et malesuada fames
ac turpis egestas. \zsavepos{mark2}Sed neque dui, laoreet porttitor lacinia vehicula,
condimentum ut dui. Phasellus viverra sollicitudin est a consectetur.
Vestibulum ante ipsum primis in faucibus orci luctus et ultrices posuere
cubilia Curae;
\verb|mark1:| (x,y)=(\zposx{mark1}sp,\zposy{mark1}sp)=(\the\dimexpr\zposx{mark1}sp\relax,\the\dimexpr\zposy{mark1}sp\relax) \par
\verb|mark2:| (x,y)=(\zposx{mark2}sp,\zposy{mark2}sp)=(\the\dimexpr\zposx{mark2}sp\relax,\the\dimexpr\zposy{mark2}sp\relax)
\end{document}
The result is given in scaled points (or sp), measured horizontally from the left of the page border, and vertically from the bottom of the page border.
Identifying the page that some label is on is already supported by LaTeX's default \label-\ref system using
% ... <stuff>
\label{mylab}
% ... <stuff>
\pageref{mylab}
zref also supports this, but since LaTeX does this by default, there's nothing more needed.
Since these methods use the \label-\ref system of LaTeX, it requires at least two compilations in order to be accurate.
