Where can I download the iPad sdk, and iPhone What is the difference?

I installed iphone_sdk_3.1.2, but can not seem to develop the iPad program can directly upgrade to iPad development environment? In addition, I put the iPad application development after a good run on the real machine is not a direct copy of the last on the list?
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ipad development SDK version to 3.2, a direct upgrade seemingly impossible. The landlord still a lot to learn how to debug it like a real machine!
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Can xcode from apple's official website dmg file, I can choose to download ipad,
But I can only run in the simulator, it is said to run on a real machine need to spend $ 99 to buy license
I would also like to know how to run a real copying machine.
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iphone and ipad sdk is a universal right of
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See it