PowenKo, WordPress Tutorial, category, Get current post of category.

reference: http://codex.wordpress.org/Function_Reference/wp_get_object_terms

$post_cats = $wp_get_object_terms( $post->ID, 'category' );
foreach( $post_cats as $cat ){
    echo '<a href="/' . $cat->slug . '" title="' . $cat->name . ' Category">' . $cat->name . '</a>';
}