Does that mean that the only things I need is to learn objective c and how to work with the SDK.nothing more nothing less
I would suggest you learn Unity instead. Learning obj-C/Xcode/iOS SDK isn't what you want for two reasons:
1 - It's too general. Those tools were made with creating any sort of app in mind, which means they're more complicated than necessary for making a game, because they weren't made with creating games in mind.
2 - It's too specific. I lied when I said "any sort of app" - I meant to say "any sort of iOS app". You won't be able to take your finished game and instantly run it anywhere else, except on an iOS device.
Unity was specifically made for creating any kind of game, for any platform. The games you make in it will run on iOS, OS X, Windows, Linux, Android, Windows Phone, BlackBerry, Wii, Wii U, DS, 3DS, PSP, Vita, PS3, PS4, Xbox 360, Xbox One, and in a web browser.
These tutorials will teach you a lot about Unity, for free, and were made with beginners in mind:
http://www.walkerboystudio.com/html/unity_training___free__.html
Beware that even after you learn how to use Unity to program your game, though, that you'll still need assets, IE, the models, textures, sounds and music for your game. Most games either have simple graphics, or are made by at least a programmer + an artist, and many are both, because producing the quality of assets you want at the sheer quantity to fill a game is difficult. I can recommend Blender for making models and gimp for making textures. Music can be done in Garage Band (but you'll want to learn a few instrument for best results... the artificial instruments can only go so far). I have no idea how good sounds are made.
Edit: Sounds and music are normally bought, I think, for indie games. IE the song Downstream from Braid's soundtrack is from Shira Kammen's Music of Waters album and predates the game by 6 years. Several of the sound effects in WarCraft 2 (and 3, for that matter) were bought from sound effect companies... not quite sure if WarCraft 2 can be counted as an indie game or not...
2X Edit: Credits for WarCraft 2 certainly look too long to me to count it as indie:
http://www.allgame.com/game.php?id=939&tab=credits
3X Edit: Maybe the first WarCraft can count as indie? Certainly was made by fewer people. But it goes to show you how many different man-hours it takes to make even simpler games.
http://www.allgame.com/game.php?id=940&tab=credits