Animated promotional video

Hi, We are launching a website and associated iPad app in the upcoming weeks and we are requiring a promotional video to explain the concept of the system and how it works. At a very basic level, details are entered into a website which is mirrored to the iPad. The iPad is then used to complete what ever the given task is. The completed data is then sent via wifi or 3G back to the website. A lot of time and effort has gone into making the website and in particular, the iPad interface very clean and simple. The promotional video will also need to be clever, simple and to the point. I've not looked to have a promo video produced before, so am not sure what you would require from me to make this job easy for you. So please outline in detail what you require from me and I will supply this to the successful bidder. I expect this video will need voice over and / or background music - this will need to be provided by you also. We look forward to hearing from you