wp_list_categories to show categories for current post
<?php the_category(); ?> or, if you want more options:
<?php the_category( $separator, $parents, $post_id ); ?> This will do the trick. It can also be used like this:
<?php $catArr = get_the_category( $id ); ?>Reference:
http://codex.wordpress.org/Template_Tags/the_categoryhttp://codex.wordpress.org/Function_Reference/get_the_category