1. Open AppleScript Editor and paste the following into a new file.
set newMac to "00:13:72:1B:FF:D1" set psswrd to "your_password" repeat with counter from 0 to 50 try set currMac to (do shell script "ifconfig en0" & " | grep 'ether '") if currMac contains "ether" then exit repeat end if on error delay 2 end try end repeat do shell script "ifconfig en0" & " ether " & newMac password psswrd with administrator privileges
2. Replace 00:13:72:1B:FF:D1 and your_password with your own MAC address and password.
3. Save the AppleScript in File Format Application and check the Run Only box. Name it something descriptive like "SetMacAdd." Save it in Applications or somewhere else where you can find it.
4. Open System Preferences and click on Accounts.
5. In Accounts click on the Login Items tab and the use the "+" to add your saved AppleScript to the list of login items.
6. Restart to check if it works.
*Systems running Tiger will use lladdr instead of ether in the script.