Consider using the comment package, available online via CTAN from:
http://tug.ctan.org/cgi-bin/ctanPackageInformation.py?id=comment
Here's an extract from the package description:
Selectively include/exclude pieces of text, allowing the user to
define new, separately controlled, comment versions. All text between
\comment ... \endcomment or \begin{comment} ... \end{comment} is
discarded. The opening and closing commands should appear on a line of
their own. No starting spaces, nothing after it. This environment
should work with arbitrary amounts of comment, and the comment can be
arbitrary text.
Other ‘comment’ environments are defined and selected/deselected with
\includecomment{versiona} and \excludecoment{versionb} These
environments are used as \versiona ... \endversiona or \begin
{versiona} ... \end{versiona} with the opening and closing commands
again on a line of their own.
Werner