The package nopageno will suppress page numbers in a whole document.
To suppress page numbers from a single page, use
\thispagestyle{empty} somewhere within the text of the
page. (Note that \maketitle and \chapter both use
\thispagestyle internally, so you need to call it after you've
called them.)
To suppress page numbers from a sequence of pages, you may use
\pagestyle{empty} at the start of the sequence, and restore
the original page style at the end. Unfortunately, you still have to
use \thispagestyle after any \maketitle or \chapter
command.
In the memoir class, the troublesome commands (\maketitle,
\chapter, etc.) invoke their own page style
(title, chapter, etc.), which you may
redefine using the class's own techniques to be equivalent to
"empty". The KOMA-script classes have
commands that contain the page style to be used, so one might say:
\renewcommand*{\titlepagestyle}{empty}
An alternative (in all classes) is to use the rather delightful
\pagenumbering{gobble}; this has the simple effect that any
attempt to print a page number produces nothing, so there's no issue
about preventing any part of LaTeX from printing the number.
However, the \pagenumbering command does have the side effect that
it resets the page number (to 1), which may be undesirable.
The scrpage2 package separates out the representation from the resetting; so one can say
\renewcommand*{\pagemark}{}
to have the same effect as the gobble trick, without
resetting the page number.
This question on the Web: http://www.tex.ac.uk/cgi-bin/texfaq2html?label=nopageno