wp_list_categories - with custom taxonomy - wordpress

Question

I'm back struggling with some more coding :(
I have written a custom PHP page to loop through a custom post type. Now what I want is to list the custom posts categories, and have each category link to the same page but pass the category to the query_posts() function.
My code is currently
<div id="left" style="float:left;width:200px">
<b>Categories</b><br><br>
<?php wp_list_categories( $args ); ?>
</div> <!-- end of left container -->
<div id="middle" style="float:left;width:700px">
<?php
$args = array(
'post_type'=> 'e-books',
'showposts' => '-1',
'eCats' => $cat,
'order' => 'ASC'
);
query_posts( $args );
where
$cat = $_GET['cat']
What I want is each link from the wp_list_categories() to be something like.
http://example.com/products.php?cat=fiction
Is this possible? I can't get my head around the Walker class :( I've got this far
class MyWalker extends Walker_Category {
function start_el(&$output, $category, $depth, $args) {
extract($args);
$cat_name = esc_attr( $category->name );
$cat_name = apply_filters( 'list_cats', $cat_name, $category );
$link = '<a href="products.php?cat="';
$link .= $cat_name;
$link .= '>';
$link .= $cat_name . '</a>';
if ( 'list' == $args['style'] ) {
$output .= "\t<li";
$class = 'cat-item cat-item-' . $category->term_id;
if ( !empty($current_category) ) {
$_current_category = get_term( $current_category, $category->taxonomy );
if ( $category->term_id == $current_category )
$class .= ' current-cat';
elseif ( $category->term_id == $_current_category->parent )
$class .= ' current-cat-parent';
}
$output .= ' class="' . $class . '"';
$output .= ">$link\n";
} else {
$output .= "\t$link<br />\n";
}
}
}
but the links aren't completing - they are showing as
?cat=

Answer 1

For listing category with the custom taxonomy :
You can you following code:
$catnames = get_terms( 'custom taxonomy name');
Then use foreach loop to disply the category.