use DateTime::Format::Strptime;

my $datetime = "2010.12.14 , 21:06:15";
my $pattern = "%Y.%m.%d , %H:%M:%S";

# lang
my $strp = DateTime::Format::Strptime->new( pattern => $pattern );
my $dt = $strp->parse_datetime( $datetime );
my $timestamp = $dt->epoch;
print $timestamp; # 1292360775

# kurz
my $timestamp = DateTime::Format::Strptime->new( pattern => $pattern )->parse_datetime( $datetime )->epoch;
print $timestamp; # 1292360775