Windows Store is slowly filling with apps in the lead-up to the unveiling (well, official launch) of Windows 8. Skype has officially added their app to the Windows Store and anybody running a preview copy (or full, MSDN, TechNet, etc copy) can download the app from the Windows Store and get in touch with friends.
The Skype App is compatible with both versions of Windows--Windows 8 and Windows RT--meaning you'll be able to use it on your shiny new Surface tablet, as soon as it arrives. The app definitely looks polished, and that is probably due in part to it being developed by Microsoft. After all, they have to make the new platform attractive to potential customers.
Skype was acquired by the technology giant for a few billion dollars, and Microsoft has been working on integrating the video chat service with its products since then. Skype should soon be making its way onto the Xbox platform as well, as Microsoft works to unify the experience across all of its platforms.