I'm planning on taking a Windows Phone, and I was wondering if it is possible to talk to FB friends via the in-built Skype app, like you can do with the desktop application on a PC.
Can anyone please quickly confirm/deny this?
I don't think this feature exists in Skype for Windows Phone.
I haven't done this, but if you link your Microsoft and Facebook accounts I'm pretty sure this is possible, for friends that have both Skype and Facebook accounts.
You can definitely open someone's page in the Contacts application and Skype them from there. I've also switched to a Skype video call from a regular phone call as well.