Skype has released its new version for MAC OS X Lion and it supports HD Video Calls between different devices. Along with other fixes, it has brought improvements to the user interface . The official Skype website says:
With Skype 5.3 for Mac OS X, you’ll also be able to send and receive HD quality video when talking to your friends and family. You’ll need to use the Mac’s built-in webcam or choose from a variety of webcams from our Skype Shop, such as the Logitech C910, to make video calls in crystal clear HD quality. To receive clear HD video calls on your Mac, we recommend an upload/download speed of 1.5Mbps.
The new Skype version is also compatible with past versions of OS X going all the way back to Leopard. Even after this new Skype release, Mac users are still considered behind in the features available for Windows users and currently lack Facebook integration.
You can download this new version of skype 5.3 from here