Google has an iOS 6 Maps app awaiting approval. It is solely up to Apple to approve.
The same sources say that Google is preparing a Google Maps app for
iOS6, which will appear in time. No official statement has been made and
there will inevitably be questions over whether Apple will approve it
in the App Store. (Apple might not, on the basis that it “competes with
existing functionality”, but would invite a further backlash if it did.