How about:

use HTTP::Date qw( time2iso str2time );

my $original  = '20100302165019';
my ($year, $month, $day) = $original =~ m{^(\d{4})(\d{2})(\d{2})};
my $time      = str2time("$year\-$month\-$day");
my $localtime = localtime( $time );
my $isodate   = time2iso($time);

print "Localtime: '$localtime'\n";
print "ISO Date: '$isodate'\n";
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Your output would be:

Localtime: 'Tue Mar  2 00:00:00 2010'
ISO Date: '2010-03-02 00:00:00'
[download]