I often see people wondering how to create unique meta tags on their dynamic PHP site. I just came across a tool that might be the answer for you. It is called phpMyMeta and is available at www.sloogle.com/. I say "might" because the description is short and I have no direct experience with the script, so I am not positive that I am interpreting the purpose of it correctly. But I thought I would point it out to you, just in case this was something you have been looking for.
The description of the tool is phpMyMeta is an easy way to manage your sites meta tags. It offers both an administrative panel where you can easily change each individual pages' meta tags. It also offers a convenient way to implement your meta tags.
This might also be useful for those of you who use a CMS product that unfortunately uses the same metas on every page. Not sure, but worth a look, if you have the need.