sWebapps is one of the fastest way to build an iPhone app.. not to be called an iPhone app though it looks like the same and you download from Appstore. What it creates is a web app for iPhone.
To me it is similar to creating a link on my home page for a website. But this does not open up the Safari app. This is nothing but an app which has nothing but a fullscreen browser which takes users directly to your webpage designed specifically for iPhone (Probably using the iPhone webkit).
I am not sure about how the submission of app part works. I personally feel that is the pain point because Apple's site doesn't accept my binary. I am yet to debug what's actually going wrong.
Though it does not get a wow, sWebapps is the first SDK out of apple for developing iPhone webapps as easy as 1,2,3
see a demo of how to, here: