With iOS 6 Apple has rebuilt the iPhone, iPod touch, and iPad Maps app from the ground-up. They've also switched away from exclusively using Google data to using data from TomTom and others. However, like any new endeavor there will be problems, frustrations, and straight up errors and omissions that need to be fixed. In iOS 6 Maps, Apple has provided a way to do just that.
That's it. Your report will be sent to Apple, and hopefully addressed in the mapping data base.
If an important location is missing in iOS 6 Maps you can use the same process to suggest it.
Apple will receive your suggested location, and if it meets their criteria, add it to the data base.
Don't forget, iOS 6 Maps ties into Yelp, so you can also add your location or business to Yelp, and that will give Apple access to that data as well.
This is basic crowd-sourcing at work. With hundreds of millions of iOS users hammering at the new Maps app, Apple and their partners will have a tremendous opportunity to iterate and improve quickly. And they'll need to.