The Microsoft-owned Skype is going through a bit of a transition at the moment, away from the desktop-centric, cheap peer-to-peer connections of old, to a more mobile-friendly client-server system. Part of this move is a new Windows 8-friendly app, which will be live and ready come Friday.
Of course, it's been Metro-ised, or whatever Microsoft wants to call it now, which means integration with Windows 8's People app. It also ties in with Win 8's always-on connection processes, which should mean less battery drain on-the-go. It's got all sorts of fancy Win 8-specific stuff too, like pinning to the side with other windows open meaning you can chat and still work, which is actually a lot cooler than it sounds.
Text-based messaging has been looked at too, which is something Skype has fallen behind on recently when compared to the likes of Gtalk. It won't come pre-installed on Windows 8 by default, unless the manufacturer you just bought your new PC from has a deal with Skype directly, but it'll be in the Windows store from launch, so there's at least once decent app in there to download. [Skype]