Under Windows, the MAC address is stored in a registry key. To change a MAC address, find that key with `regedit` and change it. Of course, Microsoft keeps moving the location of the key around!
Windows XP adds an option to change the MAC address on some network cards under the Advanced tab in the network adapter's Properties menu.
A much easier and more reliable method to change a MAC address under Windows is to use a software utility program designed to do this for you.
Macshift is a free utility that you can use to spoof your MAC address under Microsoft Windows.
or www.codeproject.com/tools/MacldChanger.asp
Under Linux, you can change your MAC address with `ifconfig
hw <class> `, or you can use the GNU MAC Changer.