What else can you do apart from calls? You can see your Facebook news feed in Skype, post status updates that can be synced with your Skype mood message, comment on friends' updates and post and 'like' them, and send SMS to them.
The Skype-Facebook integration seems to be aiming at some complementarity from both sides. Skype needed to develop a more social dimension and Facebook had some grounds to cover in terms of communication. I used to think that Facebook would come up with something like an embedded VoIP application or plugin (If I was behind Facebook, I'd seriously consider that), and that Skype would work its half-a-billion user base into something more social with some better and richer interface. You can download Skype 5.0 from there.