BetaCategory: WordPress - Owner: PaulDavis - Owner ID: 1
This specific snippet adds a rel tag with a lower-case name.
Not 100% sure where to find column names to get the data from.
<?php
$args = array('orderby' => 'name','order' => 'ASC','exclude' => '1','hide_empty' => '0');
$categories = get_categories($args);
foreach($categories as $category) {
echo '<li><a href="' . get_category_link( $category->term_id ) . '" rel="' . strtolower(str_replace(' ', '-', $category->name)) . '" ' . '>' . $category->name.'</a></li>';
}
?>