To add an excerpt to a post, simply write one in the Excerpt field under the post edit box. An excerpt can be as short or as long as you wish. Usually, given its purpose, a couple of sentences is fine.

Displays the excerpt of the current post with [...] at the end, which is not a “read more” link. If you do not provide an explicit excerpt to a post (in the post editor’s optional excerpt field), it will display an automatic excerpt which refers to the first 55 words of the post’s content.

The first tag is designed to retrieve the excerpt in plain text for manipulation in php functions, so if all you want to do is get rid of html tags, thats your answer. Just make sure you ‘echo’ or ‘print’ it, since by default it won’t render a display in your browser.

Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt ut laoreet dolore magna aliquam erat volutpat. Ut wisi enim ad minim veniam, quis nostrud exerci tation ullamcorper suscipit lobortis nisl ut aliquip ex ea commodo consequat.

Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt ut laoreet dolore magna aliquam erat volutpat. Ut wisi enim ad minim veniam, quis nostrud exerci tation ullamcorper suscipit lobortis nisl ut aliquip ex ea commodo consequat.

Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt ut laoreet dolore magna aliquam erat volutpat. Ut wisi enim ad minim veniam, quis nostrud exerci tation ullamcorper suscipit lobortis nisl ut aliquip ex ea commodo consequat. Duis autem vel eum iriure dolor in hendrerit in vulputate velit esse molestie consequat, [...]