#!/usr/local/bin/perl -w
use strict;
use File::Find;

find { wanted => sub { print if /\.pm$/ }, no_chdir=>1} $dir foreach my $dir @INC;

##</code><code>##


# use strict and the ilk above
my %been_at;
sub wanted {
   return if $been_at{$dir};
   $been_at{$dir}=1;
   print if /\.pm$/;
}
find {wanted => \&wanted, no_chdir => 1} $dir foreach my $dir @INC;