Site Owners often detest the fact that google caches an old copy of their site and displays it on searches which brings up the site pages.
A simple way to prevent robots (including Google, Yahoo etc.) from caching your site contents is to include the following within the head section of your web page.
<META NAME="ROBOTS" CONTENT="NOARCHIVE">
To prevent just Google use:
<META NAME="GOOGLEBOT" CONTENT="NOARCHIVE">
To prevent MSN Bot use:
<META NAME="msnbot" CONTENT="noarchive">
Note: MSN Bot do not indicate support for noarchive tag with the generic name ROBOTS (unlike Yahoo & Google).