How do shoutcast scripts (ie. now playing) work?

[TheDude1884]

I'm using this small php script to generate Now Playing for my web site...
/*
<?
$add = 'thedude188.no-ip.org';

################# DONT MODIFY STUFF BELOW HERE ############################



header ("Content-type: image/jpeg");
$sp = 50666;
$sock = socket_create(AF_INET, SOCK_STREAM, 0);
if (@socket_connect($sock, $add, $sp)) {
$st = 'hello satan, what are you playing?';
socket_write($sock,$st,strlen($st));
$tmp = 'NP: '.socket_read($sock,2048);
if (rand(0,40) == 24) { $tmp = $tmp.""; }
} else { $tmp = 'Server down or unreachable..'; }
$im = imagecreate (6*strlen($tmp),14);
$background_color = imagecolorallocate ($im, 0, 0, 0);
$text_color = imagecolorallocate ($im, 255, 255, 255);
imagestring ($im, 2, 0, 0, $tmp, $text_color);
imagejpeg ($im,'','40');
socket_close($sock);
?>*/

pretty simple script made by Satansomebody lol.
Anyway I was just changing some things in the script to see what the output would be on my site. I tried changing $sp to some other number and that pretty much "broke" the script . I was just wondering what can I change in this script to output max listeners or previously played or some other stats for my site.
Is there a site for out there for ppl that make scripts like this? Maybe I could make my own script to suit my own needs.
TY