This is untested but should give you an idea. There is definitely more efficent ways to do this and it'd be interesting to see other people's methods on doing this.

my $max_count = 0;
foreach my $key (keys %hash)
{
  my $count = $hash{$key};
  if ($count > $max_count)
  {
     $max_count = $count;
  }
}


foreach my $key (keys %hash)
{
   my $count = $hash{$key};
   if ($count == $max_count)
   {
      print "$key $count\n";
   }
}
[download]