Windows Phone 8 will allow VOIP apps to deeply integrate into the OS, providing support for accepting incoming calls as if they were a traditional phone call, carrying on calls in the background, and integrating VOIP apps into the People Hub.
The OS will also allow developers to completely control apps with Bing Voice. Rather than just launch an app, you’ll be able to search within an app or launch a specific feature. The new Audible app (available now), for example, will eventually let you start playing a book with your voice. Audio controls like pause, play, and next chapter will also be supported.