Basic iPhone prototype

I am in the preliminary stages of discussing the scope of an iPhone application. I need to build a prototype that functions on the iPhone. The prototype is very basic with equally basic graphics (which I will provide). Here are the details of the prototype -[login to view URL] It is important that the prototype should function on the iPhone for demo purposes, There is definitely scope for making this into a full fledged app. As this is just at the prototyping stage, my budget is limited.