I know that this is nothing secret or special for most of you, but I think there are people out there who don’t know how to do this. Long story cut short:
ifconfig $INTERFACE down ifconfig $INTERFACE hw ether $NEWMAC ifconfig $INTERFACE up
Adjust the values for interface and new-mac to fit your needs.
You may ask yourself, why you should ever need this. Well, if you are really asking yourself this question, you maybe really don’t need it …. 
Personally I need it because there is an open WiFi-network in my hometown which gives everyone the opportunity to use it for 30 minutes every day. They assure this by saving the MAC …
Alright? Alright! 
3 Comments
I thought that a NIC has a fixed MAC address which cannot be changed and persists till the end of it’s lifetime… wth?
a NIC has a fixed MAC address, of course. But the operating system can spoof the MAC
Also there is macchanger which can pick a random vendor MAC or a completely random MAC.
Syntax (as root of course):
ifconfig wlan0 down
macchanger –mac 00:11:22:33:44:55 wlan0
or
macchanger -a wlan0
ifconfig wlan0 up
The -a flag is pretty handy for this task.