Admin and user tagging plugins?

I’ve looked all over the forums and wp-plugins.net but haven’t been able to find what I’m looking for.

I’m in the process of setting up a music review site. I’m looking for a plugin that will allow users to add tags to reviews. For example, if a site is listed under rock, I’d like users to be able to add tags like “punk”, “metal” etc to the same review so its listed under different tags/categories.

Does a plugin like this exist?