Apple has provided some key new APIs to developers, include a mapping API which gives third-party applications access to Google Maps data and allows turn-by-turn navigation.

Location-based applications and services are already looming as the next big thing in mobile applications, and Apple is clearly intent on capitalizing on the buzz around them.

Apple has also added support for in-app billing, which means developers can prompt users to purchase additional content or upgrades from within the application, without having to return to the App Store. Developers can also now sell applications on a subscription basis. These features will be popular with developers as it gives them more flexibility in how they charge for their applications, but if not implemented carefully they could become a nuisance for users. Apple will need to provide and enforce clear guidelines around what developers are legitimately allowed to charge for, to prevent applications becoming spam or worse. Overall, iPhone OS 3.0 will be judged on whether it lets developers build better mobile applications than competing platforms. Providing new APIs certainly won't hurt, but the ball is now in the developers' court.

Incremental tweaks to user experience
New features include the much-requested copy and paste (which works across applications); the ability to send and receive multimedia messages (MMS); Spotlight (searching the contents of the iPhone); improved online Calendar support (but no API for applications to access calendar data); tethering to allow use of the iPhone as a cellular modem (subject to network operator approval) and push technology allowing applications to alert users when a message or event is received. Apple also improved the consistency of its user interface, adding a landscape-format on-screen keyboard across all core applications.

All of these tweaks will improve the overall user experience, without making any radical changes to what is widely regarded as the most polished mobile user interface currently available. Apple did not add support for multitasking, one area where its competitors remain ahead. The new iPhone OS does provide some insight into the next hardware revision, and the incremental nature of the software upgrade indicates that the next planned version of the iPhone will also be an incremental upgrade to the current model, with no radical changes to the device’s capabilities.

Developer tools are significant for iPhone strategy
iPhone OS 3.0 provides improvements to the developer experience, which demonstrates the extent to which Apple's strategy for the iPhone is now driven by its success in the mobile application market.

Apple has been focusing its marketing and advertising on applications, positioning the iPhone (and iPod Touch) as the best mobile platform for applications and games. The success of the iPhone App Store has stirred Apple's competitors into life, with other vendors (Nokia, Google, RIM, Microsoft, Palm) and network operators launching competing application store offerings. Apple has a big head start in mindshare around mobile applications - among consumers and developers - and the new SDK and developer tools are aimed squarely at attracting as many developers as possible, preferably away from other platforms.

The new SDK gives developers access to 1000 new APIs, which Apple claims will give applications better access to the iPhone hardware, ultimately improving the quality and variety of applications on the platform.

• What Do iPhone Developers Think of SDK 3.0 and the OS?
• What Hardware Changes Will iPhone OS 3.0 Bring?