If you look in the bottom left corner and above the comments of any post on this site you will see “Short Link: http://p.00.im/(a 3 digit number that might get longer)” which is a link to the post you are viewing that is 18 characters long counting the http:// in the url. It is only 11 characters long if you do not have to use the http:// where you are posting the link
Update:
How To:
Here is the code I used to do this. You just put it where ever you want it. I put it in the section <div class=”post-info”> section of my theme.
<?php
echo '<a href="http://1.00.im/';
echo the_ID();
echo '">http://1.00.im/';
echo the_ID();
echo'</a>';?>
Replace the “1.00.im” with your site’s URL. If you have multiple URL’s use the shortest one. There are some good short URLs available on freedns.afraid.org and just forward it to your main site without the cloaking option. Now install “Permalink Migration” to wordpress and set a second permalink from /%post_id% and save there. Now go and edit your main permalink option but don’t change anything and click save on it. Then you will have a setup similar to my short links.
