title: Easiest PHP forum to configure to work inside an existing CMS?
body: <p>I have been assigned to add a forum into an in-house CMS we have been using for some time.  The system has its own login/user system and an established user database.  Ideally I'd be looking for the easiest forum software to convert to use with our system, but if necassary can rewrite and migrate the user databases to use the forums system.  </p>
  
  <p>Does anyone have any experience rolling forum software into their own systems, or recommend forum software that has a clean and concise code-base that is easy to work with?  Any advice is appreciated at this point.</p>
  
  <p>I have been browsing through the <a href="http://php.opensourcecms.com/scripts/show.php?catid=5&amp;cat=Forums" rel="nofollow noreferrer">forums section</a> of <a href="http://opensourcecms.com" rel="nofollow noreferrer">opensourcecms.com</a> but the details available are limited.  Also, this will be running on PHP5, so one that uses some of PHP5's features would be ideal.</p>