use strict;
use Date::Manip;

$main::TZ= 'GMT';
print UnixDate(ParseDate("last Friday in February 2009"),"Last Friday 
+of the month is %B %E, %Y.");
[download]

Wow! the Date::Manip is powerful, this is exactly what I was looking for. Thanks to every for their replies. I will definitely use the methods suggested at some point. Thanks very much!

Take a peek in here: Sample Date Calculations Sample Date Calculations (with DateTime).

1. Find the day of the week of the first day of the month (using Date::Calc, DateTime, localtime or whatever).

2. Find the number of days to add or subtract.

   Days to first Monday:

   $days_to_first_monday = ($dow + 7 - 1) % 7;
   [download]

   Days to previous Friday:

   $days_to_last_friday = ($dow + 7 - 5) % 7 - 7;
   [download]

   In both case, $dow is expected to hold 1..7 for Mon..Sun or 0..6 for Sun..Sat

3. Use Date::Calc or DateTime to perform the math.

Some examples :

#!/usr/bin/perl 
use strict;
use warnings;
use DateTime;

my $dt = DateTime->last_day_of_month( year => 2009, month => 2 );

while ( $dt->mday() >= 1 and $dt->month == 2 ) { 
    $dt->subtract( days => 1 );
    print "Last Friday of February: ", $dt->ymd, "\n" and last
      if $dt->day_of_week == 5;
}

my $dt1 = DateTime->new( year => 2009, month => 1, day => 1 );

while (1) {
    $dt1->add( days => 1 );
    print "First Monday of January: ", $dt1->ymd, "\n" and last
      if $dt1->day_of_week == 1;
}
[download]

hth,
PooLpi