Mark Ghosh have upgraded and consolidated his old Contextual Related Posts Plugin for WordPress. This new version (1.1) is a simple install (just install the plugin file) and it will show the last 5 related posts from your blog. The display show the links right after the comment form. The matching is done with the post title of the post being viewed. Examples include my Retail Junction (WordPress 2.0) and Sap-Tricks (WordPress 2.0)
PS: Some theme authors tend to remove default actions from their themes. If you are having problems displaying the related posts, please check with your theme author or post a comment here for help.
Download Contextual Related Posts Plugin
Please post bugs and comments.
I have recently installed this plugin which I like very much. That said, how can I make the related posts come directly after the post text? Basically in between the bottom of the post and the first comment?