To use Kinect devices on a Mac, all we need to do is installing some libraries, libFreenect and libusb-1.0.
libFreenect provides APIs to access Kinect's functionalities. libusb-1.0-devel is a modified USB camera driver. If you have installed OpenCV via macports, you may have libusb-1.0. However, what we need for the kinect camera is the 'libusb-1.0-devel' version, which conflicts with the old libusb-1.0. If you try to install libusb-1.0-devel via macports, it will fail because of confliction. You can build a proper one from the source code.
Once both libraries are built and installed in the system, you can run a sample program in libFreenect library. I made an XCODE project by replacing the freeglut library with the Apple's GLUT.framework and tested the example on my MacBook Pro 15' (Core2Duo 2.3Ghz, Geforce 9600M GT).
It runs very well in 30 Fps mode !!