Drag and Drop in iPhone development

Hi guys , i saw some vidoe where people are allowed to drag and drop buttons to develop their application, may i know how can i get it to work in my xcode or something?

Regards,
AtomBinary

Welcome to Mac-Forums..

That's Interface Builder (IB) that helps in layout of buttons and other "views" within iOS. It doesn't allow you to "develop" application, just helps in the layout..

Depending on the version of you Xcode you are using, it's either a separate application or built in. Either way, create a new project and then double-click on the MainWindow.xib file that gets created for you and IB will start up. Now from the library there you can drag the various controls..labels, buttons, and various views and put them on the simulated screen that will appear proportional to whether you chose to develop an iPhone or iPad application.

Once this is done, you use IBaction/IBoutlets to get and set information from these various views.

If any of this zipped by a little quickly over your head, you might want take a look at the numerous iOS development books out there which will lay this out for you..

In the end, you still need to write actual Objective-C code to make your application do anything of value..

I'm using xcode 4.0 where do i get the 4.2 or better version? How do i update it? Do i need to pay $99 for that to happen?

You can download the latest version of Xcode from the Mac App Store. You don't need to pay the $99 to start developing, only when you are ready to publish an app to the App Store..