I think this is what your looking for.
http://uk2.php.net/manual/en/function.substr.php
<?php
$rest = substr("abcdef", 1); // returns "bcdef"
$rest = substr("abcdef", 1, 3); // returns "bcd"
$rest = substr("abcdef", 0, 4); // returns "abcd"
$rest = substr("abcdef", 0, 8); // returns "abcdef"
// Accessing via curly braces is another option
$string = 'abcdef';
echo $string{0}; // returns a
echo $string{3}; // returns d
?>
Hope it helps.