What are the tools required to develop iOS applications? What are the tools (hardware/software) required to develop iOS applications? Because I want to learn iPhone application development.
You'll need a Mac (any current model will do) and Xcode which can be downloaded from the Mac App Store. It comes with all the tools necessary, including a Simulator. It nevertheless is recommended to test apps on the hardware (aka an iPhone) as well.

Additional details can be found here.