jfoucher

This plugin uses the yahoo.com API to find the most relevant keywords from the content of your post, and then adds them as tags.
The tagging is fully automatic, so if you’re using a plugin like feedwordpress to display RSS feeds on your blog as posts, everything will get done as the feed posts are published. No user intervention necessary!

Auto-tags

Automatically add relevant tags to new posts.

hiddentao

Page Tagger is a WordPress plugin which lets you tag your pages just like you do with your posts. It adds a tagging widget in the page-editing view in the admin interface. Page Tagger requires PHP 5.
Detailed information including installation and usage is available at http://www.hiddentao.com/code/wordpress-page-tagger-plugin/
<h3>Known Issues</h3>
<ul>
<li>None at the moment.</li>
</ul>

Page Tagger

Page Tagger is a Wordpress plugin which lets you tag your pages just like you do with your posts. It adds a tagging widget in the page-editing view in …

Auto-tags vs Page Tagger