Develop Web Site Document Archiving & Retrieval Application

Require the development of: 1) a client administered Document archive interface with sign-on authentication to upload and edit files. 2) a corresponding Visitor's interface where they can access documents for viewing (typically PDFs) or listening (MP3s) from the current [login to view URL] web site. These 2 interfaces must integrate with the current web site which is developed using Serif Web Plus and is hosted at Netfirms.com. Ideally this simple application would be developed using PHP and MySQL, both of which tools which are positioned on Netfirms.