Tagging system

Hey,

I'm looking into making / adding a tagging system for Nexdana so users can tag games / videos / images then find content by the tags. Also be able to show tag clouds on the content menus. I've been googling about for ages now and really can't find any decent ones, the one I did find didn't have a working demo (N)

Does anyone know of a decent mysql/php script available that I can simply integrate into my current database/site

OR

the sort of structure I'd need for the database table(s) to make it work as I really can't figure it out.

Thanks in advance :D

Joe