// change cat=25 to the category ID you want
	// get the first post date in cat 25
	$lastdate = get_posts('posts_per_page=1&cat=25&order=ASC');
	list($end_date, $time) = explode(' ', $lastdate[0]->post_date);
	$lastdate = strtotime ( $end_date);

	$today = strtotime ( date('Y-m-j'));
	if(isset($_GET['newsdate']) && $_GET['newsdate']){
		$today_page = strtotime ($_GET['newsdate']);
		$yesterday = strtotime ( '-1 day' , $today_page ) ;
		$tommorow = strtotime ( '+1 day' , $today_page );
		list($year,$month,$day) = explode('-', $_GET['newsdate']);
	} else {
		$yesterday = strtotime ( '-1 day' , $today) ;
		$tommorow = strtotime ( '+1 day' , $today);
		list($year,$month,$day) = explode('-', date('Y-m-j'));
	}

	query_posts('year='.$year.'&monthnum='.$month.'&day='.$day.'&cat=25');

	if($yesterday > $lastdate) {
		echo '<a href="' . get_permalink() .  '?newsdate='. date ( 'Y-m-j',$yesterday).'">previous day link</a>';
	}

	if($tommorow < $today) {
		echo '<a href="' . get_permalink() .  '?newsdate='. date ( 'Y-m-j',$tommorow).'">next day link</a>';
	}

	if($tommorow == $today) {
		echo '<a href="' . get_permalink() .  '">next day link</a>';
	}