Try the nifty new Time::Piece module. It makes this stuff easy.

#!/usr/bin/perl -wT
use strict;
use Time::Piece;

my $date1    = "2000-11-24 03:23:45";
my $date2    = "2001-01-24 05:45:00";
my $format   = "%Y-%m-%d %T";

my $diff = abs (Time::Piece->strptime( $date1, $format ) -
                Time::Piece->strptime( $date2, $format ));

print "There are " . $diff->minutes . " minutes between $date1 and $da
+te2\n";
__END__

There are 87981.25 minutes between 2000-11-24 03:23:45 and 2001-01-24 
+05:45:00
[download]

-Blake