Blog tagging is up and running. There's a tag list in your right hand column now (Above the RSS feed links).  Let me know if anyone is interested in a tag cloud and I'll give you that option.

You can play with it on my blog.  I tagged a few posts :P  That's really the only annoying thing.  You're going to have to go back and tag your old posts if you want them to show up in the tag list :(

My Tag List

On your "Edit post" page I added a checkbox that makes the post retain its original post time.  This should make tagging old posts less annoying because now you don't have to set the post time yourself.