Rumour has it that the iPhone OS 4 will feature stronger Facebook integration, including synced contacts and messaging.

The move would put the iPhone on the same level as other smartphones that already feature Facebook integration. At the basic level, Apple is said to be planning the ability for users to sync Facebook contacts into the iPhone’s phonebook, which seems like a logical step for the device.

The integration could also include the ability for Facebook Connect to connect more directly with iPhone apps and users. This would allow developers to easily add more of Facebook’s ‘social’ features to their apps.

Business Insider also reported that the integration could include a version of Facebook’s messaging system that would allow users to send messages to Facebook contacts in the format of a text message, minus the cost of traditional texts.

Apple is no stranger to Facebook integration and has already included basic integration with the latest version of iPhoto, and with the Facebook Connect information sharing abilities in iTunes 9.

Expected to be announced during Apple’s Worldwide Developers Conference keynote on June 7th, the integrated features are likely to be announced alongside the expected new iPhone reveal.

Image via Gizmodo.