Jared Harbour

Ever want to change the url used to display your posts? This plugin 
allows a blog administrator to change a users url slug from their edit profile page.
The plugin allows for the creation of new author slugs, but also saves old slugs a user has used in the past.

Plugin Name:       Modify Author URL

Allows administrators to modify a users author url from their profile page.

Artberri

For a better SEO, it is said that the URLs must give information about the content of the web page. Because of this most people uses pretty URLs in wordpress with the permalink options. But the post slug in the URL is generated from the title of the post, and some times this slug is too long because we don’t remove the stopwords, common words without an important meaning, that don’t add anything significant to the URL.
This plugin removes the stopwords from the URLs for better SEO optimization of your blog and for making better and smaller URLs. You can set the stopwords through the `Plugins’ menu in WordPress wp-admin.
For example:
<ul>
<li>You have set the next stopwords: a, an, the, i, you, he, she, we, they, of</li>
<li>You write a post called: Review of the Google Chrome Browser</li>
<li>The normal post slug would be: review-of-the-google-chrome-browser</li>
<li>But the optimized slug is: review-google-chrome-browser</li>
</ul>
All configuration is done through wp-admin. No code editing is necessary.

Remove Stopwords From Slug

This plugin removes the stopwords from the URLs for better SEO optimization of your blog. You can set the stopwords in the admin panel.

Plugin Name: Modify Author URL vs Remove Stopwords From Slug