Someone

public function next_post_link($post)
{
	$next_link = '';
	$next_post= false;
	DB::set_fetch_mode( PDO::FETCH_CLASS );
	DB::set_fetch_class( 'Post' );
	$next_post= 
		DB::get_row( 'select * from {posts} where content_type = ? and status = ? and pubdate > ? order by pubdate asc', 
				array(Post::type('entry'), Post::status('published'), $post->pubdate), 'Post' );
	if( ( $next_post ) != false ) {
		$next_link= '<a href="' . $next_post->permalink. '" title="' . $next_post->title .'" >' . $next_post->title . ' >></a>';
	}
	return $next_link;
}
	
public function prev_post_link($post)
{
	$prev_link = '';
	$prev_post= false;
	DB::set_fetch_mode( PDO::FETCH_CLASS );
	DB::set_fetch_class( 'Post' );
	$prev_post= 
		DB::get_row( 'select * from {posts} where content_type = ? and status = ? and pubdate < ? order by pubdate desc', 
				array(Post::type('entry'), Post::status('published'), $post->pubdate), 'Post' );
	if( ( $prev_post ) != false ) {
		$prev_link= '<a href="' . $prev_post->permalink. '" title="' . $prev_post->title .'" >' . '<< ' .$prev_post->title . '</a>';
	}
	return $prev_link;
}