Our website provided a free download of WebWizard 1.1 for Mac. The application lies within Games, more precisely Board.
From the developer:
WebWizard is the OS X friendly way to play Wizard of the Coast's 'Magic the Gathering' over the world wide web! Written in Java, WebWizard is a snap to install and use on just about any platform on the planet. It's the closest thing to playing the real game as you're likely to find!
You may want to check out more software for Mac, such as Doublemill, which might be related to WebWizard.