Meta tags provide information to all sorts of clients, such as browsers and search engines. A useful contribution how Google interprets meta tags has been published on the Webmaster Central Blog (Official news on crawling and indexing sites for the Google index). Another contribution provides hints how to create good descriptions.
A script how to create dynamic META descriptions for a WordPress Blog has been published by Darren Pangan on his blog. A useful contribution about the meta description tag has been published by Christopher Heng. A script how to extract and display meta tags is available at stackoverflow website.
The standalone XML-sitemap generator provides an option to display the meta description tags in the custom sitemap list.