English manual:

What is SH-Autolink?
SH-Autolink is a plugin for Wordpress. In posts and comments, it transforms predefined words automatically into hyperlinks. 
Autolink supports the protocols HTTP, HTTPS, FTP and E-Mail.

What is SH-Autolink Super?
SH-Autolink Super is a modified version of the origianl SH-Autolink plugin. It has some additional functionality that you can read about on http://www.sethson.com/super-version-of-the-sh-autolink-plugin-for-wordpress/.

Installation
The installation is quite simple. Just copy the plugin file sh-autolink.php to your Wordpress-Plugin directory. 
After that, you can activate the plugin in the Wordpress-pluginmanager. If the plugin has been activated successfully, 
you will find the menu item “SH-Autolink” in the menu “Manage” of the admin section of Wordpress.

System requirements
Wordpress 1.5.x

Notes
The original version of SH-Autolink had instructions in German as well. I have removed those since I had modify the instructions and I don't understand German.