Iphone development
You don't need an iPhone to develop an iPhone app. You can also use an iPod Touch. If you don't want to buy any device, the iPhone SDK comes with an iPhone simulator that you can use to test your apps. However, the simulator has a number of limitations, such as the lack of accelerometers.
Note that you also need a Macintosh with version 10.5 of Mac OS X.
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If you plan to release your app on the Apple Store, it must be developed using Apple's iPhone Development Kit. The developer kit is available for download from its website. (You can use various open source developers to allow your application to run on jailbreak phones.) I think you also need to join Apple's developer program - about $ 99 or something.
The wrinkle is that the developer kit only works on macOS, so you must have Apple to develop apps. It comes with a software emulator, so you don't need to have a real iPhone.
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You don't have iPhone tech support to write an iPhone program, but you need (if you're going through regular channels without hacking) an Intel-based Mac, and testing your app on a device is 100, if not 1000 times more useful than testing in simulator.
Go to Apple's developer site to sign up as a developer (free until you want to test your device, see above) and download Xcode. This will be the iPhone SDK and iPhone simulator.
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