Keith S.

The best new feature in WordPress 2.3 is the integration of tagging into the core of WordPress. However, the tag cloud widget & functions that are included leaves a lot to be desired. So, with time on my hands, I decided to whip up my own version of the tag cloud that lets you configure the tag cloud with all the customizations (well, almost, see below) the tag cloud template tag allows.
You can find the plugin home page (and leave comments) <a href="http://keithsolomon.net/ctc/" rel="nofollow ugc">here</a>.
<h3>NOTE</h3>
Development on this plugin has STOPPED! I am looking for someone to take it over. Find more info <a href="http://wp.me/p4xrG-7q" rel="nofollow ugc">here</a>
<h3>Upgrade</h3>
I suggest using the built-in WordPress plugin update feature, but to manually upgrade, follow these instructions: 
1. Deactivate the plugin in the WordPress admin menu. 
2. Delete the existing <code>tag-cloud.php</code> file from the <code>/wp-content/plugins</code> folder. 
3. Upload the <code>tag_cloud</code> folder to the <code>/wp-content/plugins/</code> directory. 
4. Activate <code>Configurable Tag Cloud</code> through the ‘Plugins’ menu in WordPress and add the widget to your sidebar. 
5. (Optional) Add <code>ctc()</code> template tag to your theme. Can be configured either via the Options menu, or via parameters in the template tag.

Configurable Tag Cloud (CTC)

Display a tag cloud customized with your preferences in the sidebar.

D'Arcy Norman

The plugin gives users the oportunity to embed a tag cloud for a site within any page. 
When using the shortcode [tagcloud] when 
writing in the content of any page, the user includes in the page, a 
tag cloud for posts on that site.
I am working on adding the ability to set options, such as sizes, etc…

Configurable Tag Cloud (CTC) vs Tag Cloud Shortcode