Become an iPhone developer.

To be an iPhone developer, you need a set of tools to ...um... develop for the iPhone! :) Among these:

An iPhone or iPod touch. No, you can't just do everything in the sim. Trust me.
A development computer.
- I do everything on a MacBook Pro (high-end laptop.)
- Some people say you can use a "Hackintosh" (non-Apple computer) for development. I know little about that. What I DO know is: if you run into problems, the community to help you will be smaller than if you use a Mac.
- Any reasonably powered Intel-based Mac should work. Certainly any recent MacBook, MacBook Pro, iMac, Mini or Mac will do fine.
- I tend to load my development computer with maximum RAM and a big hard disk. While not technically required, this just makes things go more smoothly.
- The Software Development Kit (SDK) requires a recent version of the OS.
The SDK, which you get from your Apple Developer Connection (ADC) account.
Some instructions.
- There are oodles of instructions available on the web (including at Apple's ADC site.)
- Some are good, some less so.
- For those just starting, I tend to recommend Beginning iPhone Development: Exploring the iPhone SDK, a very well written book from which you are likely to learn a lot. (I have no connection to this book, other than being a very satisfied customer.)

In addition, one must have a fair bit of grit, tenacity and general stick-to-it-iveness. You can read more about all of that on the Developer page, "What's it like being an iPhone developer" section.