I've been using this subroutine in my code to validate dates:

# checks if date is valid
sub validate {
    use Time::localtime;
    use Time::Local qw(timelocal_nocheck);

    my $day = $shift;
    my $month = $shift;
    my $year = $shift;

    my $local;
    eval {
        $local =
     localtime(timelocal_nocheck(0, 0, 0, $day, $month - 1, $year));
    };
    if($@) {
        if($@ =~ /^Can't handle date/) {
            return 0;
        } else {
            die $@;
        }
    }
    my $c_day = $local->mday;
    my $c_month = $local->mon + 1;
    my $c_year = $local->year + 1900;
    return($day == $c_day and $month == $c_month and $year == $c_year)
+;
}
[download]

--
Ilya Martynov (http://martynov.org/)

use strict;
use Date::Calc qw(check_date);

## my ($month, $day, $year) = (2, 29, 2036); ## valid
my ($month, $day, $year) = (2, 29, 2037);    ## invalid, will set to d
+efaults

## You could use dynamic date values instead
my ($def_month, $def_day, $def_year) = (2, 7, 2002);

if (not check_date ($year, $month, $day)) {
   print "Invalid date was entered ($month/$day/$year)! ",
         "Default date will be used instead.\n";
   ($month, $day, $year) = ($def_month, $def_day, $def_year);
}

print "Using date: $month/$day/$year\n";
[download]

--Jim