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";