Say I have a string in php, that prints out to a text file like this:
nÖ§9q1Fª£
How do I get the byte codes of this to my text file rather than the funky asc
If you are talking about the hex value, this should do for you:
$value = unpack('H*', "Stack");
echo $value[1];
Reference
Use the ord function
http://ca.php.net/ord
eg.
<?php
$var = "nÖ§9q1Fª£ˆæÓ§Œ_»—Ló]j";
for($i = 0; $i < strlen($var); $i++)
{
   echo ord($var[$i])."<br/>";
}
?>
Ord() does the trick with an ASCII-charset. If you, however, meddle with multibyte strings (like UTF-8), you're out of luck, and need to hack it yourself.
If You wish to get the string as an array of integer codes, there's a nice one-liner:
unpack('C*', $string)
Beware, the resulting array is indexed from 1, not from 0!