Will Apple ever allow Android to be run on an iPhone?

This Android user strongly doubts it. While Apple has been willing to allow Windows copies to be installed on Macs via Boot Camp, VMware, etc., this has a lot to do with Windows' enormous lead in available apps, which makes it a must-have for some professionals, and a useful feature for many consumers. By contrast, iOS is currently ahead of Android in terms of available apps, and while I can see Android eventually pulling ahead, the situation would be nothing comparable to Mac-Windows at the time Boot Camp was released. Thus, it makes little sense for Apple to support a platform that's going toe-to-toe with the one that represents Apple's main competitive advantage (iOS, along with the whole ecosystem surrounding it). Moreover, since Android's development is out of Apple's control, Apple would be helpless to prevent its brand from being damaged if some iPhone buyers who installed Android had an unsatisfactory experience - and I'm sure many of them would. While I personally prefer Android, I'll be the first to admit it's a more complex and less polished platform, and those traits would definitely rub a lot of iPhone devotees the wrong way. There's also the simple matter of hardware. Aside from the sleep/wake button and volume controls, the iPhone has only one dedicated button. Whereas Android phones often have four, and perhaps also a trackpad. A lack of dedicated menu, back, and search buttons would cause major headaches for many Android builds, if not render the phone inoperable. Which brings us back to the issues of user experience and Apple's brand :).

Sales would not sky rocket.  Practically no one would run Android on an iPhone. Most smartphone buyers don't even know what Android and iOS are. The small percentage of people who did run Android on iOS would just create a disproportionate support headache and bad PR for Apple.  With the iPhone selling as well as it does, don't expect it to ever happen.  Companies generally make those kinds of moves out of desperation (Android apps on Blackberry Playbooks, for example).

You can run Windows on your Mac because you have access to the file system. Even if Apple never provided Boot Camp to users, you had the ability to wipe the system drive and install Windows on it anytime you wanted. With Boot Camp, it was an incentive for people to switch over from Windows. The idea was that you could still run any applications that you really needed to in Windows, but you could also have Mac OS X, which is what some users wanted but couldn't have due to work or other issues. When it comes to Android and iPhone, Apple doesn't feel like the user is missing out on anything coming from Android. Apple has more apps, which was the reasoning behind Boot Camp in the first place so you could run your Windows apps, and there are very few, if any applications that run on Android that don't run on iOS. So to answer your question, no I don't think that Apple will ever let you run Android on your iPhone. That being said, there's a group of intrepid hackers out there that have gotten Android to work, but it still isn't fully finished and will eat your battery in about 4 hours. If you're really that interested, go ahead and Google iDroid and you should be able to find their website, which contains instructions on how to install Android on your iPhone, although there are device restrictions as well.

First of all, the only people who can give you an authoritative answer to this question work at Apple, and definitely would not give you an authoritative answer. The rest of us can only speculate. That said, it would be surprising and contrary to Apple's direction with iOS so far for them to do this. They maintain very strict control over what kind of code can be run under iOS: they don't allow browsers that aren't based on MobileSafari (such as Firefox) because (at least in part) they have different javascript interpreters outside Apple's control. Apple doesn't allow game emulators except when they come pre-packaged with the games they're going to emulate, so that Apple can evaluate all the code that will be running on the platform. So an Android runtime where any old Android app could be run would be wildly out of character. If that huge hurdle could be overcome, the next issue would be performance. Apple would not want a large class of apps that ran poorly. Porting Dalvik and the Android API to iOS would be a big undertaking that would impose inevitable performance hits. I have to wonder if there's a team outside of Apple that could optimize it for Apple's hardware.

Could you get Android OS to run on an iPhone? Most likely, if you use someone else's knowledge or know enough about the phones and Operating Systems to do such a thing. But will Apple ever allow it? Let me ask you a similar question: "Will the US Government ever allow citizens to own their own Nuclear Missles?" No offense intended, I just couldn't help myself.

Sure, Apple will allow it, since jailbreaking is legal under the DCMA provisions. I would not expect Apple to help you porting it over though. Unlike the x86 world, there aren't any ARM standards for booting operating systems, plus drivers have to be rewritten. I would not discount the enormous amount of work that has gone into making Windows run on just about every hardware configuration out there, it's the main reason why even if Apple wanted OS X to run on any computer, it would be a daunting task to do so. Regardless, Apple locks the boot loader to prevent people from screwing up their phones. It's not because of malice towards Android (that's what courts are for).