Besides the RT module, you have the option of using the Measurement Hardware Development Kit (DDK) to interface Mac OS X with DAQ hardware. There is a link below to the DDK.
Measurement Hardware Driver Development Kit (DDK)
http://sine.ni.com/apps/we/nioc.vp?cid=11737〈=US
FAQ: Mac OS X and National Instruments
http://digital.ni.com/public.nsf/websearch/C152D1B507EA342486256B7A006E9D7C?OpenDocument
Regards,
Todd D.