iPhone: What you need to know

Aside from the question of whether it's actually a useful product, the iPhone has been a massive success for Apple in purely marketing terms. The company that seems incapable of putting a foot wrong at the moment has stolen the limelight from all its competitors, including the once-untouchable Google.

However, by stepping out of its computing comfort zone into the highly competitive mobile market, some commentators are predicting that Apple is pursuing a risky strategy. Rather than seeing an opportunity and filling it — as the company did so successfully with the iPod — the iPhone feels more like a defensive move to prevent handset makers from eating into Apple's portable music business.

Despite being positioned as a consumer device, the iPhone could also be a useful business tool, due to the fact it makes use of Ajax programming methodology. This means applications can be developed once and applied to any hardware in an organisation with minimal fuss.

First reviews of the iPhone have been broadly favourable. The Wall Street Journal's Walt Mossberg claims high points include an excellent web-browsing interface and impressive battery life. Missing features include no instant messaging, and no way to access Apple's iTunes store directly.