//get cool feedburner count
$whaturl="http://api.feedburner.com/awareness/1.0/GetFeedData?uri=your feedburner id";
//Initialize the Curl session
$ch = curl_init();
//Set curl to return the data instead of printing it to the browser.
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
//Set the URL
curl_setopt($ch, CURLOPT_URL, $whaturl);
//Execute the fetch
$data = curl_exec($ch);
//Close the connection
$xml = new SimpleXMLElement($data);
$fb = $xml->feed->entry['circulation'];
//end get cool feedburner count
Replace "your feedburner id" with your actual FeedBurner ID. Also, make sure your "Awareness API" is turned on in your FeedBurner settings for the particular feed you are pulling from.