[Gary King]

If you're talking about vBulletin's function, here is what it looks like:

PHP Code:

function dowordwrap($text) {
  global $wordwrap;

  if ($wordwrap!=0 and $text!="") {
    return preg_replace("/([^\n\r ?&\.\/<>\"\\-]{".$wordwrap."})/i"," \\1\n",$text);
  }

} 


Where $wordwrap is the number of letters before wrapping, and $text is the text to wrap.