Today Skype announced the 5.3 update for Mac OS X which brings HD video calls to Lion among a handful of other UI enhancements and bug fixes. The official Skype blog explains:
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.
While previous versions of Skype, even 2.8, seem to run rather well on Lion, official support should iron out any bugs you’ve been noticing since upgrading. The new update is not only available for Lion users, however, Skype’s blog post notes it is also compatible back to Leopard.