In the spirit of TMTOWTDI, here's another way of doing it, which only needs to make one localtime call. Of course, you also have to store around a little extra data (the months), but it's probably worth it. More descriptive variable names are always helpful too, of course. :)

my($hour, $mday, $mon, $year) = (localtime)[2..5];
my @months = qw/jan feb mar apr may jun
                jul aug sep oct nov dec/;

$mday-- if $hour < 9;
printf "Location: http://www.userfriendly.org/cartoons/archives/%02d%s
+/%04d%02d%02d.html\n\n",
    $year%100, $months[$mon], $year+1900, $mon+1, $mday;
[download]

(By the way: when posting code you should use the <code> tags so that your code looks, well, like code. Read more in Perl Monk Procedures.)