Flash to PHP -> Creating a User Defined Directory

Okay, so I know how to use Flash with PHP to allow users to upload files to a directory on my server. What I want to do now is allow users to create directories on my server. Ultimately what will happen is that the user will type in their name (which will be used to name the directory on the server; for example, if a user types in “John” as the user’s name, I want PHP to create a folder “/_parent/John”) and then select files on their computer to upload to the server ("/_parent/John/image01.jpg").

Attached is the code I have for the image uploader (FLA, SWF, and PHP). I need help with the custom directory creation, both the Flash side as well as the PHP side. I can’t imagine it’s too difficult, but I have minimal experience with PHP and haven’t done much with Flash concerning this kind of project. This is just for reference, though, I’m not asking for anyone to finish my project. I just want the basic script for Actionscript and PHP on how to do this.

Thanks so much, everyone! Any help/suggestions are greatly appreciated.