Apple rumoured to release iOS 4 software today

Apple is scheduled to make its iOS 4 operating system available for download later today, according to various reports.

The update is expected to be available for the iPhone 3G, iPhone 3GS, iPad and post-2009 iPod touch devices.

Apple claims that the operating system - which will come preloaded on the new iPhone 4 - will contain 100 new features, allowing users to have a unified inbox with messages organised by threads and the ability to open attachments in third-party apps.

Wireless keyboard support will be provided via Bluetooth, spell check will work in Mail, Notes and other designated apps, and 5x digital zoom will allow closer detail of subjects.

Portable Apple devices will also be able to multi-task for the first time, but this option will be restricted to the iPhone 4 and 3GS models.

Users will have to connect their device through a USB port to upgrade. Apple has yet to officially announce a time, stating only that the update is "coming soon".