Would it be possible to make an app that has a home page which is "local" on the device but when certain options are pressed it accesses webpages corresponding to the options pressed. Might not make a lot of sense but...

Home page of the app > Option 1 (webpage) > rest of the website

Then when the home button is pressed on the site it takes them back to the home screen of the app. If you need more detail please go a head and ask.

If it is possible; How would it be done? Basically I want to have an HTML website with CSS etc but run it off an iPhone app. I can use objective-c to write the app home