Wanted to help if I can and didn't know where to post this.

Problem: When a popular tag is shown that is long, it extends over the template
or
Tag size is just too big

Solution:

If you know what you're doing, you can change the font sizes in /include/PEAR/HTML/tagcloud.php

For instance... if you want all tags to appear the same size, you can do what I did. There are two variables that you need to change and 3 places in the file to change them.

This is how the code is now:

Code:
var $baseFontSize = 24;
    /**
     * @var    int
     * @access var
     */
    var $fontSizeRange = 12;
To have them all be 12px change the first variable to 12 and the second to 0. This makes the base font size 12 pixels and tells the script not to change any size.
Code:
    var $baseFontSize = 12;
    /**
     * @var    int
     * @access var
     */
    var $fontSizeRange = 0;
To have the popular tags still emphasized, but in a smaller text than 24. Set your base font to something smaller but also be sure to change the range to accomodate.

This example sets the popular tags to 18px while the others stay at 12px (18-6=12):
Code:
    var $baseFontSize = 18;
    /**
     * @var    int
     * @access var
     */
    var $fontSizeRange = 6;
The other places to change it looks like this:

Code:
    // {{{ function __construct($baseFontSize = 24, $fontSizeRange = 12)
    /**
    *
    * Class constructor
    *
    * @param   int $baseFontSize    base font size of output tag (option)
    * @param   int $fontSizeRange   font size range
    * @access  public
    */
    function HTML_TagCloud($baseFontSize = 24, $fontSizeRange = 12)
Hope this helps someone. :D