Luke Mlsna

Plugin that allows you to easily give individual posts and pages an HTML meta description from the edit post/pages admin area.
<h3>Readme Generator</h3>
<ul>
<li>This plugin’s readme.txt file was generated by the <a href="http://shinraholdings.com/tools/readme-gen/" rel="nofollow ugc">Readme Generator</a> for WordPress Plugins.</li>
</ul>
<h3>Support</h3>
<ul>
<li><a href="http://shinraholdings.com/plugins/meta-description" rel="nofollow ugc">Plugin Homepage</a></li>
<li><a href="mailto:plugins@shinraholdings.com" rel="nofollow ugc">plugins@shinraholdings.com</a></li>
</ul>
<h3>Donations</h3>
<a href="http://shinraholdings.com/donate" rel="nofollow ugc">Donations</a> are graciously accepted to support the continued development and maintenance of this and all our other plugins. We currently accept Paypal, link backs, positive ratings, and kind words.

Meta Description

Adds a meta box to the edit posts/pages admin area for inputing an HTML meta description.

hitmax1978

Find the post. Click “Edit post”. Activate the “Text” tab of your post.
To modify the title tag of your post, add a simple string into your post content: 
<!—title=”your title”—> (See screenshot-1)
To modify the description tag of your post, add: 
<!—description=”your description”—> (See screenshot-1)
IMPORTANT!!! Be sure after “<!” characters you have two “-” characters. It is similar to HTML comment tag.
Multilingual support
If some kind of multilingual plugins are active (for example Multilanguage by BestWebSoft) – you can define titles and descriptions in other way: (See screenshot-2)
English locale (United States) 
<!—title_en_US=”your title”—> 
<!—description_en_US=”your description”—>
Українська локаль 
<!—title_uk=”Ваш заголовок”—> 
<!—description_uk=”Ваш опис”—>
Русская локаль 
<!—title_ru_RU=»Ваш заголовок»—> 
<!—description_ru_RU=»Ваше описание»—>
Feedbacks are welcome. Visit <a href="http://onlineservicetools.com/meta-tags-from-content-wp-plugin-discussion-feedbacks" rel="nofollow ugc">onlineservicetools.com</a>

MetaTagsFromContent

Good in multilingual site

Generates title and description tags from post's content.

Meta Description vs MetaTagsFromContent