Usage:

use DateTime::Format::Human::Duration qw( );

my $formatter = DateTime::Format::Human::Duration->new();

sub format_duration {
   my ($dur) = @_;
   return $formatter->format_duration($dur,
        past   => '%s ago', 
        future => 'in %s', 
        no_time=> 'now',
   );
}
[download]

Creating the argument is done using the same code as Re: smart human readable time epoch.

I'm still getting bad results, though. I think the module has a few bugs.