Get physical and virtual subdirectories of the document root in PHP

I have a set of Web applications, all of which are hosted in a single Apache instance:

/*
/
  /WebApp1
  /WebApp2
  /...
  /Common            not a Web application, just a set of utilities!
*/

I want to make a general home page (/index.php), which basically displays the list of Web applications available. So, since PHP is my server scripting language of choice, I would like to know if there is a PHP function I can use to retrieve an enumerable collection of the physical and virtual subdirectories of the document root.

---

Additional info: I don't know if it's necessary to specify this, but my Web applications run on Windows servers. My development machine runs Windows 7 x86 Ultimate; the test server runs Windows Server 2003; the we开发者_StackOverflow社区bsite must also run on Windows Server 2008.

---

Use glob() on your document root directory ?