How can I find where I will be redirected using cURL?

To make cURL follow a redirect, use:

curl_setopt($ch, CURLOPT_FOLLOWLOCATION, true);

Erm... I don't think you're actually executing the curl... Try:

curl_exec($ch);

...after setting the options, and before the curl_getinfo() call.

EDIT: If you just want to find out where a page redirects to, I'd use the advice here, and just use Curl to grab the headers and extract the Location: header from them:

$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, $url);
curl_setopt($ch, CURLOPT_HEADER, true);
curl_setopt($ch, CURLOPT_FOLLOWLOCATION, false);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
$result = curl_exec($ch);
if (preg_match('~Location: (.*)~i', $result, $match)) {
   $location = trim($match[1]);
}

Add this line to curl inizialization

curl_setopt($ch, CURLOPT_FOLLOWLOCATION, true);

and use getinfo before curl_close

$redirectURL = curl_getinfo($ch,CURLINFO_EFFECTIVE_URL );

es:

$ch = curl_init($url);
curl_setopt($ch, CURLOPT_HEADER, false);
curl_setopt($ch, CURLOPT_USERAGENT,'Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8.1.13) Gecko/20080311 Firefox/2.0.0.13');
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_BINARYTRANSFER, true);
curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
curl_setopt($ch, CURLOPT_FOLLOWLOCATION, true);
curl_setopt($ch, CURLOPT_CONNECTTIMEOUT ,0); 
curl_setopt($ch, CURLOPT_TIMEOUT, 60);
$html = curl_exec($ch);
$redirectURL = curl_getinfo($ch,CURLINFO_EFFECTIVE_URL );
curl_close($ch);

The answer above didn't work for me on one of my servers, something to to with basedir, so I re-hashed it a little. The code below works on all my servers.

$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, $url);
curl_setopt($ch, CURLOPT_HEADER, true);
curl_setopt($ch, CURLOPT_FOLLOWLOCATION, false);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, TRUE);
$a = curl_exec($ch);
curl_close( $ch ); 
// the returned headers
$headers = explode("\n",$a);
// if there is no redirection this will be the final url
$redir = $url;
// loop through the headers and check for a Location: str
$j = count($headers);
for($i = 0; $i < $j; $i++){
// if we find the Location header strip it and fill the redir var       
if(strpos($headers[$i],"Location:") !== false){
        $redir = trim(str_replace("Location:","",$headers[$i]));
        break;
    }
}
// do whatever you want with the result
echo redir;