Mac OS X driver 4.76-3 supports all Wacom tablets with USB connection, i.e. USB tablets of the Intuos2 Series (XD), Intuos Series (GD), Graphire2 (ETA), Graphire (ET), PenPartner (CT) and the Interactive Pen Displays Cintiq 18sx, 15x, PL-500 & PL-400. Note: ADB and serial tablets are not and will not be supported on OS X.
This driver requires Mac OS X v.10.1.5 or 10.2 or later and supports BOTH the native and classic environment of OS X.
More info and download link here.