Help implementing tagging on PD.

I’m sick of having defined categories for Purleydreaming. Having anything ‘fixed’ is always a bottleneck so I want to jump on the ‘tag’ bandwagon. The actual code behind moving the literature website from categories to tags is easy enough. It’s quite straight forward. I’m having problems figuring out how to layout the database so it works as efficient as possible. My first thought was to just ad a ‘tags’ field to each submission to PD thus implementing tags. That of course wouldn’t work very well when you wanted to make a tag cloud representing the most popular tags. Ontop of adding all the tags in an extra field on the submitted works table I could just make a ‘tags’ table that had the tag id, tag word, and the count updated every time someone submits something. That sounds alright but how do I work in searching and organizing by tags? That I supposed would be another table referencing tags to submissions. I can’t seem to think of a better way. I know there has to be a better way then that. How the heck do you setup your database to implement a tagging feature?

I could make it work with what I just explained but I believe there is a better way and since I’ve re-designed databases because I seriously f*cked them up from the start I’ve learned that’s not what I want to continue doing. Any pointers or suggestions would be greatly appreciated.

—- UPDATE —-
I ran across this site which explains a few tags database schemas and has essentially solved my initial question with a question of ‘which of these methods or DB schemas should I use’. I’m leaning more toward the Toxi solution. Seeing those schemas in some relation to delicious is calming. I’ll se how it works out for me.