Deeper Facebook integration could be part of iOS 5.1 with evidence in the latest beta version suggesting the fruition of a long-rumoured partnership between the social network and Apple.

As noted by the iMore website, several references are made to Facebook in the code of iOS 5.1 beta 3. This suggests that some features of micro-blogging service Twitter that are already built into iOS such as the ability to send images directly from the camera roll to your Twitter feed could be about to come to Facebook as well. 

Facebook integration was thought to be coming to iOS 4 but the two companies reportedly couldn't agree on finer details of the deal, such as which company could 'own' the announcement. 

iMore also spotted references to the iPad 3 in iOS 5.1 beta 3 - the codenames J1AP and J2AP - which have been spotted elsewhere before. 

Earlier this week it was rumoured that Apple is planning to hold an early February event to announce the iPad 3 and iOS 5.1.