Here is a short script which works fine in PHP 2 but not in 3. I have looked in the FAQ and the bug database, but did not see anything on this particular problems:

<?
$new = "One";
$$new = "Two";
echo "1: $new<br>2: $$new<br>";
echo "1: $new<br>2: $One<br>";
?>

on PHP3 produces the output: (bad.. I think)

1: One
2: $One
1: One
2: Two

and on PHP2 produces: (Good... or was)

1: One
2: Two
1: One
2: Two

So... is this a bug or feature? Sorry if it's been covered!