本篇文章由：http://xinpure.com/php-based-on-information-such-as-the-ip-address-in-your-city/

获得IP地址

在 PHP 中得到当前访问者的IP地址，还是比较简单的:

$ip = $_SERVER['REMOTE_ADDR']

将IP转换为城市等信息

淘宝提供了一个IP数据接口: http://ip.taobao.com/service/getIpInfo.php?ip=ip地址

$response = file_get_contents('http://ip.taobao.com/service/getIpInfo.php?ip='.$ip);
$result   = json_decode($response);print_r($result);

输出结果为:

stdClass Object
(
    [code] => 0
    [data] => stdClass Object
        (
            [country] => 中国
            [country_id] => CN
            [area] => 华南
            [area_id] => 800000
            [region] => 广东省
            [region_id] => 440000
            [city] => 深圳市
            [city_id] => 440300
            [county] =>
            [county_id] => -1
            [isp] => 电信
            [isp_id] => 100017
            [ip] => 183.16.191.102
        )
)

参考链接: http://bbs.csdn.net/topics/390668296