Okay, let me just update my previous post. As it turns out, this plug-in is working in WordPress 3.0.4, BUT, in order to get it to display related posts under EACH entry, you need to add the code snippet in your theme’s “single.php” file.
If you add it to the theme’s “index.php” file, related posts will only appear one time at the bottom of the home page, right above the footer.
In fact, as I did with the “index.php” file for the TwentyTen theme, I also added some extra CSS code to “single.php” so that the category name and tags look much nicer, and are enclosed in a round-cornered box. I in fact took some of the code from “index.php” and put it in “single.php”.
The related posts list is located right below the comments box.
If you would like to see an example, go to my blog at the following URL, and then click on any of the “Recent Posts” links that are in the sidebar on the right side of the page:
https://www.endtimeprophecy.net/Blog/
So, in short, this plug-in is working in 3.0.4 on single post pages.