I recently learned iPhone Development, it is so easy and interesting. You just need basic knowledge of programming and object oriented concepts.
Lets begin.

Tools Required:
IDE for Programming : X-Code available only on MAC Machines

Programming Language : Objective C
Objective-C is the primary programming language which provides object-oriented capabilities and a dynamic runtime has elements that are unlike any language you’ve probably experienced, so sit back and enjoy your journey into the world of Objective-C.
Objective-C inherits the syntax, primitive types, and flow control statements of C and adds syntax for defining classes and methods.Objective-C source code program files usually have .m file name extensions, while header files have .h extensions, the same as for C header files.
It also adds language-level support for object graph management and object literals while providing dynamic typing and binding, deferring many responsibilities until runtime.

Basic Concepts of Objective C
Basic Structure and concepts of Objective are same as normal object oriented programming language.
1. Program Structure
2. Basic Syntax
3. Data Types, Variables, Constants, Operators, Loops, Decision Making, Functions,  Blocks,  Numbers,  Arrays, Pointers, Strings, Structures,  Preprocessors, Typedef, Type Casting,Log Handling, Error Handling,Command-Line Arguments
4. Class,Methods,Protocols,Inheritance
5. GUI Forms and Pages
6. Event Handling
7. Networking
8. Database Connectivity

Development Approach
X-Code is like Visual Studio, just drag n drop the controls  and write code associate to it. It is done using X-Code with the help of Storyboard. Storyboard is nothing but the flow of the project, which transition from page to page.
Storyboard shows the flow of form to form,page to page, programmer can understand the flow of the app. But the problem is you need to create separate class foe each control you are using in GUI and link both of them.
And also assign the delegate to them.A delegate is an object that acts on behalf of, or in coordination with, another object when that object encounters an event in a program. Delegate are nothing but event handlers. This is little bit complex process. If you forget to link class to GUI control and delegate, application will not work as per expectation.

So, I  have chosen to develop iPhone App throughout programmatically. It is very much easier for me.
When We create app throughout programmatically you just need to do following the following steps.
1. Create Object of the Control (Here called as view)
2. set properties ot it.
3. Set location.
4. Add to the view controller on which you are going to add the control.
5. Write method to perform the work as per event specified for the control.
And Done.It is same as the creating object of GUI Object and adding it of form like in JAVA.

One thing you need to do, By default root view is selected as per storyboard. While creating apps, by default it contain storyboard,but it should not, So delete Story bard from project and its reference too. Set you base view controller as root controller in AppDelegate.m. By this, You view controller will display first.

Here, list of links for learning iPhone Development.
Reference :

Why iPhone Development ?
Highest-Paying-Programming-Languages-You-Should-Learn :
http://www.businessinsider.in/These-Are-The-Highest-Paying-Programming-Languages-You-Should-Learn-Ranked-By-Salary/articleshow/45223268.cms

About IDE:
https://developer.apple.com/library/ios/referencelibrary/GettingStarted/RoadMapiOS/FirstTutorial.html

How to starte iPhone Development?
Getting-Started-with-iPhone-and-iOS-Development
http://www.codeproject.com/Articles/88929/Getting-Started-with-iPhone-and-iOS-Development

Create-iphone-app-programmatically-in-its-entirety
http://stackoverflow.com/questions/2530121/create-iphone-app-programmatically-in-its-entirety

Your First iOS App: 100% Programmatically
https://medium.com/@austinlouden/your-first-ios-app-100-programmatically-67cc41319bd8

Basics of Objective C:
https://developer.apple.com/library/mac/documentation/Cocoa/Conceptual/ProgrammingWithObjectiveC/Introduction/Introduction.html
http://www.tutorialspoint.com/objective_c/

Enjoy iPhone Development.

Friends if you have any questions feel free to post them in comment, I will be happy to answer all you queries.