First off i will give a very BASIC explanation of MAC addressing. For more information on this topic MuderMouse wrote a nice tutorial that can be found on the Informationleak site. Basically every Network Interface Card or NIC is assigned a Media Access Control or MAC address. This means you have a different mac for every NIC on your system. I have three. One for my normal ethernet card, my wireless card, and one for my modem.
How to spoof your MAC
There are many programs out there that claim they do this for you. In this tutorial i will use the program i used, and the one I found the easist to use. It is called MacMakeUp and can be found Here
This process is pretty simple. First select the NIC for which its MAC you would like to spoof. There is a drop down menu at the top. Next you need to pick a new MAC to change it too. Enter this into the box labeled MAC address. Do not put :’s between the sets of hex characters.
Wrong way: “0a:0f:8b:9e”
Right way: “0a0f8b9e”
After you do this just click change and you should see some text output at the bottom of the program telling you that it worked alright. (I would recommend writing down your original MAC address in case you want to change it back.) Congratulations you have just spoofed your MAC address.
There are many different this you can do with this. I will leave most of them up to your imagination. However i will cover one that I used this for. Basicly this can be useful for connecting to wireless networks with mac address filtering. All you are doing is making the router think you are somone that you are not. If you are able to access the list of MAC addresses that are allowed to connect to the network, you could change your MAC to this one, thus making the router think that your are that specific computer (one that is allowed to connect to the network.)
Remember that you are responsible for your actions.