Meta information for Tag Archives

Hi guys,

I’m working on my sites SEO and we just have so many posts that we leave categories incredibly broad while tags are more specific search terms. My tag pages then are quite important and are ranking incredibly low as a result of them not having any specific meta data and having cookie-cutter titles. I know with tools like HeadSpace you can get custom meta data for categories, but that doesnt really help me as category terms are so broad anyway. Has anyone figured out how to do this with tag archives?

Really hope I can find an answer to this! Cheers,