How NSXMLParser works with iTouch/iPhone

Hello,

Pardon my ignorance, but how does NSXMLParser work in terms of prompting the user to connect to the internet before actually running.

Is it safe to assume that my app will always have internet connectivity (either 3G or wifi) whenever it is available?

I've gone through the (really helpful) tutorial over at http://theappleblog.com/2008/08/04/tutorial-build-a-simple-rss-reader-for-iphone / and I think I understand most of it. However, I am under the impression that the iPhone always has internet connectivity (either 3G or wifi) whenever possible so my app doesn't have to worry about that stuff. Is that a good assumption?

I this post made sense.

Thanks,
Mark