解决php插入数据到mysql中文乱码问题

$str = iconv('gbk','utf-8',$str);

    header("Content-Type:text/html;charset=utf-8");
?>

Create TABLE `net_city` (
`cityid` smallint(4) NOT NULL auto_increment,
`cityname` varchar(80) NOT NULL default '',
`provinceid` smallint(2) NOT NULL default '0',
`inarea` varchar(5000) NOT NULL default '',
`outarea` varchar(5000) NOT NULL default '',
`tel` varchar(400) NOT NULL default '',
PRIMARY KEY (`cityid`)
) ENGINE=MyISAM DEFAULT CHARSET=utf8;
PHP里的代码：
$conn=mysql_connect("localhost", "用户名", "密码");
mysql_query("set names 'utf8'",$conn);
mysql_select_db(" www.111com.net 数据名",$conn);
$exec="insert into net_city (cityname,inarea,outarea,tel) values ('".$link_cityname."','".$link_inarea."','".$link_outarea."','".$link_tel."')";

$result=mysql_query($exec,$conn);
if($result){
       echo "1";
     }else{
        echo "0";
     }
mysql_close($conn);

if (!$con) { die('Could not connect: ' . mysql_error()); }

mysql_select_db("my_db", $con);

mysql_query("SET NAMES GBK");  //GBK处为编码设置

$sql="INSERT INTO person (FirstName, LastName, Age)VALUES('$_POST[firstname]','$_POST[lastname]','$_POST[age]')";

if (!mysql_query($sql,$con))

{ die('Error: ' . mysql_error()); }

echo "1 record added";

mysql_close($con)

?>