The Rating plugin 1.0b (beta) release is on my site and in the downloads section on this site. If you have any problems, post them in the forums here or on my site. Please also post any feedback/suggestions.
This plugin allows you to add a rating system to any item. You can add them with autotags, or with a slight modification to the core files. Full details will be posted on my site soon.
I would also like to ask Dirk and the guys: please would you think of some way that a plugin can contribute code to stories and other items, so that it is not necessary to modify core files to add a rating.