ehabsan

This plugin enables you to easily add as many tags as you wish in one round, i tested it on my localhost to add 1000 tag and everything worked fine.
you can also specifiy a slug by using the following format tag,slug, a working example will be:
<pre><code>tag1
tag2,slug2
</code></pre>
When you don’t specifiy a slug the tag name will be used as the slug, so in the previous example 2 tags will be inserted tag1 with tag1 as the slug,and tag2 with slug2 as the slug
You can also edit a function that will be used to modifiy the tags you insert, if you wish to edit that function go to the directory where this plugin was installed and then to the admin directory, open the filter-tags.php file and edit that function.
You will see that function in this plugin’s settings page, however it will only be read-only so you can make sure that the tags will be modified as you expect them to be.

Quick Bulk Tags Creator

Easily add tags in bulk, and easily create a filter function to modifiy the values you insert

Boone Gorges

This plugin inserts a link into the Post Tags box on the post edit screen that allows users to select from the most popular tags on the entire WPMU install.
Developed for the CUNY Academic Commons. Visit http://commons.gc.cuny.edu to learn more about this bitchen project.

Sitewide Tag Suggestion

Creates "choose from most popular sitewide tags" function on post edit screen

Quick Bulk Tags Creator vs Sitewide Tag Suggestion