What's the difference between iPhone, Blackberry and Android?

And what other brands of smartphones should I be aware of? I don't know too much about smartphones.

The operating system. It's like asking the difference between a PC and a Mac.

Blackberry is fighting for survival at the moment; I wouldn't be surprised if they were out of business in five years. The real fight is between iOS (Apple iPhone) and Android (manufactured by many). I have both but personally prefer my Android.

For iOS you have only one choice - Apple iPhone. For Android, look at the Samsung Galaxy series, the HTC - 1 Max and the Motorola Razor.

IPhone is the Apple smartphone brand
BlackBerry is a company, formally known as RIM
Android is a mobile operating system developed by Google
There's also Microsoft's Windows Phone.

All of them are smart phones the only difference is operating system
ios:
only iphones run on ios. Ios has over 9 lacks apps that can be downloaded from app store
pros: high security, premium quality, good hardware, excellent performance
cons: too many restrictions and high pricing

Android:
android is a free open source( any one can use it and modify it) so it has wide range of phones from budget phones to premium phones. Android has over 10 lakhs apps that can be downloaded from play store. It has 1 lack apps more than iphones app store but many apps in play store are use less

Blackberry:
blackberry has its own blackberry operating system based on java its has less apps when compared to android and apples iphone. It is famous for its blackberry messanger(now available on android and iphone)
at present blackberry is struggleing it may quit

additionally there are smart phones which run on windows os, symbian (presently not continued), java based os(low priced phones)