I prefer DateTime::Format::DateManip over the module you have selected. This provides an object with all the exposed methods allowed for DateTime while still providing some parsing of date strings.

#! C:/Perl/bin/perl
use Modern::Perl;
use DateTime::Format::DateManip;

my  $dt = DateTime::Format::DateManip->parse_datetime( 
               "2011-07-24T17:46:33Z" 
          );
say $dt;
# Lock down the parsed time zone
    $dt->set_time_zone( 'UTC' );
say $dt;
# change the time zone
    $dt->set_time_zone( "America/North_Dakota/Center" );
say $dt;
[download]

Output

# 2011-07-24T17:46:33
# 2011-07-24T17:46:33
# 2011-07-24T12:46:33
[download]