Check if a URL exists.

function url_exists($url) {
@ $headers = get_headers($url);
    return preg_match('/^HTTP\/\d\.\d\s+(200|301|302)/', $headers[0]);
}

<?php
// Test script. Function created by SecondVersion
function is_valid_url($url)
{
    $url = @parse_url($url);

    if (!$url)
    {
        return false;
    }

    $url = array_map('trim', $url);
    $url['port'] = (!isset($url['port'])) ? 80 : (int)$url['port'];

    $path = (isset($url['path'])) ? $url['path'] : '/';
    $path .= (isset($url['query'])) ? "?$url[query]" : '';

    if (isset($url['host']) AND $url['host'] != gethostbyname($url['host']))
    {
        if (PHP_VERSION >= 5)
        {
            $headers = implode('', get_headers("$url[scheme]://$url[host]:$url[port]$path"));
        }
        else
        {
            $fp = fsockopen($url['host'], $url['port'], $errno, $errstr, 30);

            if (!$fp)
            {
                return false;
            }
            fputs($fp, "HEAD $path HTTP/1.1\r\nHost: $url[host]\r\n\r\n");
            $headers = fread($fp, 4096);
            fclose($fp);
        }
        return (bool)preg_match('#^HTTP/.*\s+[(200|301|302)]+\s#i', $headers);
    }
    return false;
}

if(is_valid_url("http://namepros.com"))
{
	echo("w00t for Namepros.com! It's alive!");
}else{
	echo("Oh no! Where did NamePros go!?! :(");
}

?>