Yes folks, thatīs right...
More then offen you want to access that juicy Mikrotik-hotspot for example, you already sniffed
a valid mac-address, but there is no tool out there to change it in OSX. well, there still isnīt, but playing around with Backtrack and VMware Fusion I found a workaround.

Tested on Alfa036H

1. connect your card to Backtrack
2. type:
macchanger wlan0 (or whatever it is) --mac=XX:XX:XX:XX:XX:XX
3. Connect to your AP with wicd (maybe not necessary)
4. Now disconnect you wificard in VMWARE
5. Start the "Realtek USB Wlan Client" (the blue crap)
6. The MAC should be the one you chose in Backtrack.
7. Enjoy

I found that I sometimes had to reboot to make that work.
OSX has to create a new interface with that MAC.

If anyone has a more elegant way of doing this, please POST !!