1. How much will it cost to own an iPhone? We already know that the cheapest iPhone will be far more expensive than the most costly Cingular phone to date. But what will the cost? What will the data plans cost? Will the Yahoo e-mail push option be extra?

2. What will be the "unlocked" iPhone price? Prices quoted by Jobs -- $599 for the 8GB model and $499 for the 4GB phone -- are the discounted prices that require a two-year Cingular contract. Will it even be possible to buy an iPhone without a wireless contract and without a specific wireless carrier?

3. How much will it cost to replace a lost or damaged iPhone? Let's say you shell out $600 for an iPhone, then two weeks later you drop and destroy it. How much will it cost to replace? $600? $1,200? More? When you buy a phone with a contract, you nearly always get a huge discount because you're signing up for the service. $150 phones are free. $200 are $50. The Pearl, for example, is $200 with the contract, but if you replace it, the replacement is $400, because you don't get a discount. How much will replacement insurance cost? Wireless carriers offer third-party insurance to cover this high replacement cost -- usually a few dollars per month added to your cell-phone bill. Will the insurance for the iPhone cost $5 or $15 per month? We don't know. If it's $15 per month, for example, that adds $540 to the price of the phone over three years. Not trivial.

4. How fast is the iPhone? Touch-screen devices are often ruined by a delay when you press the on-screen virtual buttons. Apple may solve this problem with its first-release product, but if it doesn't, a persistent lag will degrade the user experience. Jobs said the "iPhone runs OS X" and "desktop-class" applications. But will the OS and applications perform with desktop-class performance? If so, Apple will have solved another problem nobody has ever been able to solve.

5. What did Jobs mean when he said the "iPhone runs OS X?" Is it the "core" of OS X with a new mobile UI? Or is the "core" new, with OS X-like UI code on top? Jobs already hinted that special iPhone applications -- not standard desktop applications -- will run on the phone. What is the iPhone's operating system, really?