See DateTime and DateTime::Format::Strptime.

use DateTime::Format::Strptime qw();
print DateTime::Format::Strptime
    ->new(
        locale => 'en',
        pattern => '%a %b %d %T %Y',
        on_error => 'croak',
    )->parse_datetime('Fri Jun 16 18:04:03 2012')
    ->strftime('%m %d %T %Y');
# '06 16 18:04:03 2012'
[download]

2012-06-16 was a Saturday, not a Friday. If you regularly get wrong weekdays in your input datetime stamps, remove the pattern %a, it will work fine without it. If you can change the output format, please use a standard format such as DateTime::Format::RFC3339 instead! This will increase interoperability.

use DateTime::Format::RFC3339 qw();
use DateTime::Format::Strptime qw();
print DateTime::Format::RFC3339
    ->new
    ->format_datetime(DateTime::Format::Strptime
        ->new(
            locale => 'en',
            pattern => '%a %b %d %T %Y',
            on_error => 'croak',
        )->parse_datetime('Fri Jun 16 18:04:03 2012')
    );
# '2012-06-16T18:04:03+00:00'
[download]