Android and the iPhone OS aren't just phone systems: they're platforms, locked in a war to decide the future of portable computing.
It took nearly 20 years for the billionth PC to be sold, but analysts predict that by 2012 there will be more than three quarters of a billion smartphones in circulation.
That's a huge market, and Apple and Google would both like the biggest slice of it.
While both players have world domination in mind, they're going about it in very different ways. Apple offers a closed, proprietary system with peerless marketing, an excellent user interface and strong ties between hardware and software; Google prefers open-source apps, spreading awareness via word of mouth and a hands-off approach to the hardware.
Android was quick to react to the iPhone's weaknesses, but the new iPhone 3.0 firmware addresses many of these, with MMS, cut and paste functionality and tethering
That means that both platforms offer copy, cut and paste, MMS and stereo Bluetooth, but the iPhone also offers accessory support, parental controls, peer-to-peer connections (via Bluetooth) and Voice over IP.
The iPhone still doesn't offer background processing for third-party applications, however, which makes Android the better multitasker.
One of the most interesting things about the iPhone 3.0 update is its new support for accessories. Developers will be able to write software that communicates with connected peripherals, either wired (via the dock connector) or wirelessly (via Bluetooth).
Apple has already demonstrated an application that ensures diabetics take the correct amounts of insulin by connecting a blood sugar monitor to the iPhone. Other examples might include pedometers and external input devices (such as games controllers or keyboards for people who prefer real keys to on-screen ones).
Although both platforms are mobile computing platforms that include phone features, rather than phone operating systems, the philosophies behind them couldn't be more different. Apple, as ever, is very controlling.
Applications can't be sold without Apple's approval, they can't operate in the background when other applications are running, and they can't duplicate the features of the core apps. That means no Safari rival (while there are web browsers in the App Store, they're just front-ends for Safari) and nothing else that competes with Apple's own apps.
Android is much more open. You can build any kind of app that you like and take advantage of any features that you want to use. The rules resemble a typical ISP contract or web hosting agreement, making sure that you don't feature illegal content, hate speech, pornography, copyright violations or "create a spammy user experience." The only non-competition clause asks you not to create apps that provide an alternative to the Android Market.
Both platforms take 30 per cent of application revenues, although Android is free to sign up to, while Apple charges developers $99 per year. However, there are more subtle differences between the two. The Android Market offers a basic sales channel and doesn't automatically notify users of updated apps like the iPhone does.
The new iPhone 3.0 update, on the other hand, goes one step further, giving developers the option to add in-game purchasing of content, such as add-ons for games, or to charge subscription fees rather than one-off payments.