#PHP - 77 Chars#

    <?while(array_sum($a)!=72){for($i=0;18>$i++;){$a[$i]=rand(3,5);}}print_r($a);

Much like sgrieve's solution, this builds a list of 18 holes, checks total par, and either prints it or rejects it and tries again. Oddly enough, our two solutions are the same length.

Rather annoyingly, PHP doesn't offer array functions with any brevity of name. Array_sum and print_r are killing me. Suggestions welcome.