iPhone Programming for newbies

Objective-C is a reflective, object-oriented programming language, which adds Smalltalk-style messaging to the C programming language, Objective-C being a strict superset of C. Today it is used primarily as the default programming language on Apple's Mac OS X and iPhone OS: two environments based on, although not compliant with, the OpenStep standard. For all of the "classic" programmers that are just getting started, you should know from now that with Objective-C, you will need to take care of the objects from the creation time up to the destruction time as iPhone programming through Objective-C doesn't offer so far Garbage Collector implementation, so it's very delicate programming style.

XCode

Xcode is a suite of tools for developing software on Mac OS X and IPhone OS, developed by Apple; it includes all the tools you need to create, debug, and optimize your applications. At the heart of the Xcode tool package is the Xcode IDE, a graphical workbench that tightly integrates a professional text editor, a intuitive graphical interface builder, a robust build system, a debugger, and the powerful GNU compiler collection which is capable of targeting Intel and PowerPC regardless of the host platform.

Instruments

Instruments is a brand-new, timeline-based performance visualization tool that gives you the ability to see how your application works like you've never been able to do before. It lets you watch CPU, disk I/O, memory usage, garbage collection, events, and more, in the form of graphs tied to time. Basically you will work with Instruments all the time during the development of your application in order to eliminate "memory leaks" and also inspect the CPU usage to avoid "battery killing".

Interface Builder

Interface Builder is the intuitive, easy-to-use tool for creating and editing user interface resources files (nib files). These files represent a set of interface objects, properties and object relationships, as well as their connections to your application's logic. If you're familiar with other RAD systems you might find a bit awkward the fact that the Interface Builder doesn't generate any code for the objects defined in it, storing all information in a XML based .nib format.

iPhone Simulator

The iPhone simulation environment lets you build and run your iPhone application on your computer. You are building an application and you haven't got a device yet? No problem, iPhone Simulator will do the business. Just like using a real device, the iPhone simulator emulates real touch, multitouch and accelerometer based actions like: tab, double tap, touch and hold, swipe, flick, drag, pinch and many others. Still, you must be very careful in getting used with the simulator because the real experience in iPhone Programming is with the iPhone Device. The main reason is that the real device is constrained by hardware limits (for example, only 400 or 600 MHz single core processor, not even close to what your Desktop might have) and you should really consider that in projecting and developing your applications.

The "Experience"

The first few steps you definitely want to do before starting is to search over the Internet for some advices on how to start, where you can find some beginner tutorials. First of all, create a developer account (which is free). On the main page of the developer account you will find some great starting Videos and also Starting Documents. If the lecture will become boring, you can just start with the Videos for the beginning.
Other great sections are: Sample Code: where you can download some Apple Samples of applications which will definitely help you a lot.

Beside what Apple is offering, I am recommending also iPhone Dev SDK Forum which is a great community with starting developers and also experienced ones, which are very communicative and kind to give us a helping hand.
The other great resource I've found and it seemed incredibly useful for me was the CS193 iPhone Programming course of Standford, I definitely recommend you those videos. They really helped me to better understand and follow some great principles of iPhone programming.