文字编码的转换mb_convert_encoding() 
mb_convert_encoding( $str, $encoding1,$encoding2 ) 
$str,要转换编码的字符串 
$encoding1,目标编码,如utf-8,gbk,大小写均可 
$encoding2,原编码,如utf-8,gbk,大小写均可 
实例1 
<?php
$str='毛票票:http://www.maopiaopiao.com';
echo mb_convert_encoding($str, "UTF-8"); //编码转换为utf-8
?>
<?php
$str='毛票票:http://www.maopiaopiao.com';
echo mb_convert_encoding($str, "UTF-8", "GBK"); //已知原编码为GBK,转换为utf-8
?>
<?php
$str='毛票票:http://www.maopiaopiao.com';
echo mb_convert_encoding($str, "UTF-8", "auto"); //未知原编码,通过auto自动检测后,转换编码为utf-8
?>
PHP下编码转换函数mb_convert_encoding与iconv的使用说明