Different page rank for same page

Google is indexing four different URL's for my home page .com, .com/, .com/index.php, and .com/index.php? and are giving them all different page rank. I know this has to be messing my page rank up. What can I do to make Google combine all of those into just .com ?

cloaking..

How about with www in front of the domain name and without, does the PR differ as well? Reason I ask, I had a client that had different PR's with the www and without. Needed to setup his htaccess file to tell google that both sites were the same so the PR would be assigned property. Also like drat stated, are you cloaking at all?