Business Power Point Marketing & Training Presenation

We require a professional Business Power Point presentation to be made that will market and explain the use of a web based application. We are just marketing this or promoting it to an internal company audience but it still needs to be expertly marketed. It will not just market but explain the application at a user training level. A full explanation of the details of the application must be included. We should be able to use it as a training tool as well. This will be divided into phases which will tie-in to the deployment of our application releases. The first presentation will cover our release 2. There should be a release 3 maybe 4 and 5. Can voice be incorporated into a Power Point presentation? If not, then your recommendation would be appreciated.