Waterloo Plugins

Tag Cloud Widget adds a simple tag cloud widget that you can use anywhere on your blog. This plugin looks at all your tags and displays them in a widget. The more times a tag is used, the larger the tag is.
Each tag is a link to the tag page (e.g. http://your-site.com/tag/your-tag). This will help with SEO.
Currently, there aren’t any options to customize the tag cloud. It should work well out of the box. In the future, there may be options to customize the widget.

Good

A tag cloud widget with links to your tag pages

Barry Kooij

Never5

With this plugin you can add tags to pages like you can to posts by default. The plugin also adds a new widget to display the page tags.

Page Tag Cloud

This plugin allows you to add tags to pages and display them in a tag cloud widget.

Tag Cloud Widget vs Page Tag Cloud