It's bound to happen -- Apple and Google aren't exactly on speaking terms. Google is pretty well rooted in the iPhone with their search and Google Maps -- and users like it. I'm not sure I know anyone who is upset that their only choice for maps on iPhone is Google.
Apple and Google's relationship hasn't exactly been stellar -- and it's starting to show. Apple acquired a company called Poly 9 that makes their own Google Earth-like app. It doesn't look as good as Google's, but it's something they can polish up, and give to their users. Of course, once Apple has their own, apps like Google Earth on the iPhone will be removed from the Market citing duplicate functionality.
Apple had already acquired a company called Placebase (a competitor to Google Maps). So now that Apple owns technology that is equivalent to both Google Earth and Maps, I don't think it's going to be long before we start seeing them inside the iPhone.