use Date::Manip;

$date1=&ParseDate('2004-10-28');
$date2=&ParseDate('2003-10-23');
$delta=&DateCalc($date1,$date2,\$err,1);

print $delta."\n";

##</code><code>##

YY:MM:WK:DD:HH:MM:SS (the years, months, etc. between the two)