Well, new tablet computer from Apple iPad has made a sensation in developers’ world. Everyday many new iPad apps are being registered and many are in queue.

iPad application development is same as iPhone application development. If you have developed some iPhone applications , developing an iPad application will be a routine job for you. But, if you are new in this field so need following things-

1- Mac Machine - You need a Mac Computer first.

2-iOS SDK - iOS SDK 4 includes a complete set of development tools for creating applications for iPad, iPhone, and iPod touch, including the Xcode IDE, iPhone Simulator, Instruments, Interface Builder, and more.
Download the iOS SDK from the iPhone Dev Center
These two things will make your job easy. Since all iPhone, iPad applications are developed in Objective C . A C like language with Object Oriented features.  iOS SDK provides you a complete IDE to develop and run your applications.

Yeah , for more information – check this