Apple has officially released the iPhone 3.0 software update for the iPhone and iPod Touch.

Users can download the update by connecting the devices to a Mac or PC equipped with iTunes. iPhone users will receive the update for free, while iPod Touch users will be asked to pay $10 (£6).

The update was first announced in March, and is the largest to be issued for the iPhone since version 2.0 last summer.

Among the new features are voice memo recording, multimedia messaging and Apple's Spotlight search software. Developers have also been given new tools offering push data updates and access to iPod libraries.

Apple has tied security fixes into the new software to address vulnerabilities which could allow the theft of data or the remote execution of malicious code on a targeted device.

Apple is issuing the software update just days before the new iPhone 3G S is set to debut in the US. In addition to increased storage capacity, the new handset will sport a faster processor and more memory.

The hardware updates will offer faster performance and the ability to record video.