Besides to buy an iOS device : iPhone / iPod or iPad, you are free to download the development tools : Xcode from Apple. In my mind : It's far better than Visual Studio !
You can download Xcode in Apple website : http://developer.apple.com
To start learning write an iPhone program, I recommand a product to you :
It's a shortcut course that you can learn how to write an iPhone Apps or iPhone Games in 4 weeks with NO programming skills and sell in AppStore. Normally, to program in iPhone you must learn and mastering C# programming language. The learning period cost months and years to come. But after you watch the step-by-step course, you can save your valuable time with less efforts - And the most important : You make money faster and quicker with your own Apps!
Secure your copy now before the special price ended.
To your success,
Ronald
iPhone Developer