@MyBackDoor - innovation vs. invention
So, basing this on the published rumors and my assumptions, the innovations here would be Apple integrating the reader into the home button - it would be touched hundreds of times a day, in a phone that gets dropped, gets touched with sweaty and dirty fingers, etc. but still needs to be able to read your fingerprint pretty reliably. If it takes several attempts each time you want to unlock your phone, most will turn it off and go back to using a PIN.
If you ever played with the fingerprint reader on your laptop, you know what utter pieces of shit the common 'swipe' variety are, and they don't use the impression variety because they cost more - Apple will have had to massively drive down the cost of that type in order to include it in a phone that is typically sold at a $200 BOM. There may be some invention required here also, in this case by the former Authentec employees.
The other part of the innovation would be to make it useful to do something beyond just unlocking your phone. That's nice, but it really only saves two seconds and makes your phone safe from shoulder surfing. If that's all it does, it is just a gimmick.
But if you could use it to approve mobile payments (possibly using NFC, though bluetooth or wifi would also work) or used by your banking app in place of entering a password, or used by the security entrance to your building, etc. then it would be more useful. Consider just the mobile payment case. If you want secure mobile payments, you need to authenticate yourself to the phone when you approve the charge - otherwise anyone who steals your phone can buy stuff with it. But you don't want to have to enter a pin and risk dropping your phone or the stuff you have in your other hand. A simple button press that authenticates you and accepts the charge solves the problem nicely, and could be done without even taking the phone out of your pocket unless it is using NFC (unless the reader is at hip level and you can sort of rub up against it lol)
All this would take a ton of legwork to set up and provide a simple seamless experience for the user, not only do you need to get all the developer APIs in place (which they've already done) but you need to talk to payment processors, major banks, companies that make biometric security equipment etc. and do a lot of joint development work with them to make it work smoothly. If you wonder why mobile payments are about 0.00001% of sales in the US, it is because no one has done this - just adding an NFC chip to a phone isn't innovating anything, it is just adding a feature to a phone and leaving it up to someone else to figure out a way to make it useful.
As many have pointed out, the Motorola Atrix had a fingerprint scanner. It was the only phone (that I know of) that had one, because they just glued one of the cheap swipe models onto the side of their phone sort of like NFC chips are slapped into phones now, without doing any sort of innovation to make it actually useful. Since it wasn't useful no one else "copied" this "innovation". If Apple adds a fingerprint scanner and makes it useful, many people will say that Apple copied the Atrix, when it will really be all the Android phones that later add fingerprint scanners that will be copying Apple - copying Apple's innovation of making the fingerprint scanner useful by doing much more than just sticking one on a phone.