MCC sells a device called iPort (I wonder if Apple is ok with that?).
Here's the link:
http://www.mcc-us.com
They sell a set of LabView VIs for $750. Their iPort RS232 I2C device sell from $200 to $400 depending upon what speed you want to operate at (100kHz vs 400kHz clock).
I have not tried these devices nor the LabView development kit they sell. I'm looking to purchase an I2C device to interface with a Visual C++ application in the next couple weeks.
