From this presentation we learn that Netweaver Cloud Integration is not “SAP PI in the cloud”, but comes very close to it. Netweaver Cloud Integration is fully compatible and integrated with the on-premise version of SAP PI. Same development, configuration and monitoring approach.
Also interesting is the blog entry of Prasanna Burri where he talks about using Netweaver Cloud Integration with SuccessFactors. In his answers to questions, Prasanna mentions an availability date of Feb. 2013.