Developing an iPhone/iPod application(barcodescanner)

Dear Sir or Madam, we need an iPhone application running in the background and integrating a fullscreen browser. The aim is to develop a barcodescanner fulfilling following criteria: - barcode detection every 10 seconds - while running the barcode detection the possibility of using another application should be given. That means that the screen of the camera should be hidden by another application. - the barcode detects information about a user(username and password). The information shall be passed to an executing login form. - if there is no barcode detection anymore the user shall be logged out.