Looks for user-defined phrases in posts and automatically links them to specified URLs. Example: Link every occurrence of "WordPress" to wp.org.
This plugin is provided "as is" and without any warranty or expectation of function. I'll probably try to help you if you ask nicely, but I can't promise anything. You are welcome to use this plugin and modify it however you want, as long as you give credit where it is due.
But please don't redistribute this plugin from anywhere other than right here. Unless months go by and it looks like I've completely abandoned this thing, let's not get forks going without a darn good reason; that just confuses people. But send me your improvements and I'll add them in and include a shout-out to you here.