If you have migrated your WordPress blog from another blogging platform but the post slugs weren’t generated, you can my Generate Post Slugs Plugin to have the slugs generated from the post title.
Why I Wrote This Plugin
I wrote this plugin for use on this very blog because when I ported my custom blog software entries to WordPress, I didn’t bother to generate slugs with the import script I cobbled together. A few weeks ago I made my URLs SEO-friendly and realized that all those posts I imported years ago were missing slugs.
By downloading, you acknowledge that this plugin is released under the GPLv2 License AS IS with no implicit or explicit warranty of fitness for any purpose. While I have tested the plugin with WordPress 3.2.1 and have used it to fix the slugs for posts on this very site, it is STRONGLY SUGGESTED that you make a backup of your WordPress installation prior to using it.
Getting the Plugin
If you accept the license terms outlined above, click here to download the Generate Slugs Plugin.
Installing the Plugin
Installation is just like any other WordPress plugin. On the plugin install page in your WordPress Dashboard, upload the zip file. Then activate the plugin under the Installed Plugins menu and follow the instructions provided there to use the plugin to generate your slugs.
I hope this helps someone.