Hello,
Let me make a suggestion. From your responses it appears you need to understand how webservices work. I suggest you take a look at how to do that. There are many languages that you can use, .NET, PHP, Ruby, etc.
You have to expose data in XML or JSON, like others have said. Once you do that, your iPhone app can consume that data. From there, you can either just display it or save it to a data model in your app, see Core Data.
There is nothing built into IIS to do this automatically. IIS is a web server. A person requests a page and that data is returned. It is up to you, the programmer, to set that up. There are many tutorials available. If your web site is running on IIS, then most likely Microsoft.net is installed. You can visit Microsofts web site and download Visual Studio Express and create your web application and expose your data.
Start there and you will be able to accomplish what you are wanting to do.