Version 2.0.0 beta of Similar Posts, Random Posts, Recent Posts, and Recent Comments have just been released. They each have their own page now; they have been tested to work with the upcoming WordPress 2.1 release; and each plugin has its own independent admin options page.
Some functionality has been re-jigged, a lot of new stuff added, and the output is now much more configurable. Check the help page for the full details.
Great Plugin, congratulations 🙂