After some 6 months of beta testing, version 4.0 of Skype has finally arrived, bringing with it a host of new features including a revamped instant messaging system and an all-new interface for ease of use. Video size, quality, and performance are also a primary focus in this release with a number of changes to bring this feature to the forefront.

For starters, full screen video is now available and for the first time it is now possible to initiate video calls rather than switching to video after first making voice contact. A built-in bandwidth manager will also optimize video quality to make the best of lower bandwidth connections, while those with faster internet access and dual-core (or better) equipped computers can enjoy up to maximum of 30 frames per second.

Voice hasn't been ignored either. Skype claims that a new audio codec delivers 'wideband' quality for 50 percent less bandwidth and again this is optimized by the bandwidth manager. Other changes include improvements to the instant messaging interface giving users more space in which to compose a message, and clearer indication of who wrote what and when.

There was no mention of an update for the Mac and Linux versions, though. For Windows users the new Skype 4.0 is available here - let us know your thoughts in the comments box.