PHP, 180
--------


    <?php error_reporting(0);$b=$argv;$b[0]='';foreach($b as $a)$c[strlen($a)]++;for($t=1;$t<=max(array_keys($c));$t++){echo $t.'|';if($c[$t])for($z=0;$z<$c[$t];$z++)echo'#';echo"\n";}

Usage:

    php histogram.php Very long strings of words should be just as easy to generate a histogram just as short strings of words are easy to generate a histogram for.
    1|##
    2|#######
    3|#
    4|#######
    5|###
    6|#
    7|##
    8|##
    9|##