client upload and download php program

Hello: I want a upload and down load program that I can send files and clients can uplod files to me.. must be php and have user and admin..... very similuar to this one [login to view URL] must have all the same features, MUST BE ABLE TO SHOW WORKING VERSION, does not have to be custom made may be out of the box but must be customizable as the above sample and have unlimited users, PK Web Designs