To change your mac address at Leopard OSX there is a little ‘trick’ that is required. The regulair command with ifconfig does not do the job.

Start your terminal and run:

Airport

1. Enable airport but disconnect from network.
2. /System/Library/PrivateFrameworks/ Apple80211.framework/Versions/A/Resources/airport -z
3. sudo ifconfig en1 lladdr [new mac]

Ethernet

1. no Fix yet, if you know any let me know.