Search engines like Google often fetch your site description from ODP (Open Directory Project) description instead of fetching it from the site content or meta-tags. This may not always be desirable as it may not represent your site properly. However luckily you can specify whether search engines can use ODP titles & descriptions. To prevent all search engines (that support NOODP) from using the titles and descriptions from DMOZ, enter this line in your meta tags:

To specifically prevent Google from using this information, use the
following:

To specifically prevent MSN from using this information, use the
following:

Once you add one or more of these meta tags to your page, it may take some time for the search engines to update your site in their listings.