Autodesk announced that AutoCAD will be returning to the Macintosh operating system starting with AutoCAD 2011. Not only will it be available on OS X, Autodesk has also slated Project Butterfly to graduate from Autodesk Labs to become AutoCAD WS for use with the iPhone, iPad, and iPod Touch mobile devices. source: Autodesk
Autodesk has slowly been providing support back to the Mac for some time now. Some programs becoming native like Autodesk Smoke, and others showing support in bootcamp or parallel modes with a Windows license. Not only will Autodesk fully support the product on the OS environment, it will also provide full 100% DWG compatibility between Windows and OS X.