oishikazuo

Self Shortener is a WordPress plugin to be able to handle URL shortening 
feature, by your WordPress site itself.
Self Shortener can:
<ul>
<li>create short URL using your site URL.</li>
<li>generate random short URL key, by specifying key length.</li>
<li>specify fix URL key instead of random generating.</li>
<li>handle I18N message. Currenly supports English and Japanese.</li>
</ul>
See http://giraffy.jp/products_en/wordpress/selfshortener/ . 
(In Japanese, http://giraffy.jp/products/wordpress/selfshortener/ )

Self Shortener

URL Shortener handled by your WordPress site itself.

dpoakaspine

Redirects a post (or any other any post-type) with a custom field <code>’redirect’</code> to another URL

Redirect Post to URL

Does what it says great

Redirects a post (or any other any post-type) with a custom field ’redirect’ to another URL

Self Shortener vs Redirect Post to URL