You have to change the format of the pages field which deals with page ranges of articles, incollections etc. in the bibliography. (There's also a pagetotal field for the total pages of, e.g., books.) The optional argument of \DeclareFieldFormat takes a comma-separated list of entry types for which the new/changed format should apply.
Changing the format for in-text-citations requires to fiddle with the postnote field; see section 3.11.3 of the biblatex manual for details.
\documentclass{article}
\usepackage[style=authoryear]{biblatex}
\DeclareFieldFormat[article]{pages}{#1}%
\usepackage{filecontents}
\begin{filecontents}{\jobname.bib}
@article{Bli74,
author = {Blinder, Alan S.},
year = {1974},
title = {The economics of brushing teeth},
journaltitle = {Journal of Political Economy},
volume = {82},
number = {4},
pages = {887--891},
}
@incollection{Fis00,
author = {Fischel, William A.},
year = {2000},
title = {Zoning and land use regulation},
maintitle = {Encyclopedia of law and economics},
volume = {2},
booktitle = {Civil law and economics},
editor = {Boudewijn, Bouckaert and de Geest, Gerrit},
location = {Cheltenham},
publisher = {Elgar},
pages = {403--442},
}
\end{filecontents}
\addbibresource{\jobname.bib}
\begin{document}
Some text \autocites[887]{Bli74}[403]{Fis00}.
\printbibliography
\end{document}

EDIT: iennisei's answer makes me think I may have misunderstood your question: In case you don't only want to drop the prefix for article page ranges, but to omit them entirely, use the following code (which makes the above format redefinition superfluous):
\AtEveryBibitem{%
\ifentrytype{article}{%
\clearfield{pages}%
}{%
}%
}

texmffolder and change it. For instance, in many styles you could remove (or comment) the line that says\printfield{pages}under\DeclareBibliographyDriver{article}. – ienissei Jan 4 '12 at 13:27