Announcement has come from Skype of the release of the beta for version 4.0

Read an early review of the new software.

From the GigaOm review:

The new client is going to cause an uproar amongst many Skype loyalists used to the IM-like nature of the current software. With this version, the software takes up the entire PC desktop screen, mostly to accommodate a growing number of features. I found it hugely annoying as it forced me to constantly toggle between the client and the desktop; merely doubling or tripling the size of the client seems like it would have sufficed.