ini_set does not seem to work with register_globals and 
magic_quotes. Example: You call a file and include the 
query string "test=hmm". Here is the code for the file:

<?php
ini_set("register_globals", "0");
echo "register_globals setting: 
".ini_get("register_globals")."<br/>";

echo "\$test value: $test";
?>

This will generate the following output:

register_globals setting: 0
$test value: hmm

Notice that the value "hmm" is still there even though 
register_globals is off according to the ini_get line.