A few Facebook users have started seeing a Call button randomly show up when they visit their friends' profiles. The new button doesn't seem to do anything, but it's not too big of a stretch to guess that Facebook wants to start doing VoIP calls.
Facebook likely will not develop the technology on its own. After all, the social networking giant has been working on deep integration with Skype to deliver SMS and voice/video chat using Facebook Connect for the last four months, if not longer. With the release of Skype 5.0 for Windows three months ago, we saw Facebook phonebook and browsing integration in the new Skype client.
Will we soon see Skype integration on Facebook? Admittedly, nothing actually suggest Skype in these leaks, but we're hoping for it anyway; these screenshots are easy to fake, but we don't really see any motivation to do so.