I'm on version 2.8. What i did instead was to go to the comments.php inside the theme folder and find this line:
<input type="text" name="url" id="url"
value="<?php echo esc_attr($comment_author_url); ?>"
size="22" tabindex="3" />
<label for="url"><small>Website</small></label>
and comment it out like this
<!--<p><input type="text" name="url" id="url"
value="<?php echo esc_attr($comment_author_url); ?>"
size="22" tabindex="3" />
<label for="url"><small>Website</small></label></p>-->
It removes the field completely where a comment author can enter a URL which is great for future comment. To also remove the hyperlink overall from the author name (like I needed to because I had close to 100 comments already with author name hyperlinked) I found the following instructions (thank you techallica.com)
1. Go to the wp-includes directory in your wordpress installation via ftp, locate a file called comment-template.php (in older versions of wordpress you would need to find comment-functions.php) , download the file, create a backup of the file to make sure you can upload a working copy in case you mess up.
2. Open the php file with notepad (any text editor) or any code editing software you may have. Do search and locate a function called: get_comment_author_link()
You will see the line:
$return = "<a href='$url' rel='external nofollow'>$author</a>";
Replace that with:
$return = $author;
These two solutions did the trick for me.