For our twenty-first century kids, technology is their birthrightWhen I recently upgraded my iPhone 3G to the 3Gs (after almost 1 year, so I got the discount) I had to decide what to do with the old one. My 4-year-old son was clamoring for it, and I said OK. But then I thought about it. Its a pretty expensive, complex, breakable, adult device. Should a 4-year-old really have an iPhone?