Child Categories

I have nested categories and want to list the child categories if parent category is selected.

That is no brainier as I was able to list them with the following code

if (is_category()) {
$cat = get_query_var('cat');
$catlist = wp_list_categories('echo=0&orderby=id&show_count=0&title_li=&use_desc_for_title=1&hide_empty=0&child_of='.$cat);
if ($catlist) {
echo $catlist;
} else {
//process the loop
}
}

But I also want to show the category description alone the Child category Name.
What is the best way to handle that. Is there a way to get the children categories id in an array? so that I can process each and grab the description.