Changing MAC address In Windows XP/Vista and Linux

I guess you've never heard of this tutorial, but I am here just to repeat it.
Ok go directly to the problem...!!!!

There are two ways change MAC address on Windows.

Method #1: Changing MAC address by changing NIC properties from Device Management System.

This is depending on the type of Network Interface Card (NIC) you have. If you have a card that doesn’t support Clone MAC address, then you have to go to second method.

a) Go to Start->Settings->Control Panel and double click on Network and Dial-up Connections.

b) Right click on the NIC you want to change the MAC address and click on properties.

c) Under "General" tab, click on the "Configure" button

d) Click on "Advanced" tab

e) Under "Property section", you should see an item called "Network Address" or "Locally Administered Address", click on it.

f) On the right side, under "Value", type in the New MAC address you want to assign to your NIC. Usually this value is entered without the "-" between the MAC address numbers.

g) Goto command prompt and type in "ipconfig /all" or "net config rdr" to verify the changes. If the changes are not materialized, then use the second method.

h) If successful, reboot your system.

Method #2: This should work on all Windows 2000/XP/Vista systems

a) Go to Start -> Run, type "regedt32" to start registry editor. Do not use "Regedit".

b) Go to "HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\ Control\Class\{4D36E972-E325-11CE-BFC1-08002BE10318}". Double click on it to expand the tree. The subkeys are 4-digit numbers, which represent particular network adapters. You should see it starts with 0000, then 0001, 0002, 0003 and so on.

c) Find the interface you want by searching for the proper "DriverDesc" key.

d) Edit, or add, the string key "NetworkAddress" (has the data type "REG_SZ") to contain the new MAC address.

e) Disable then re-enable the network interface that you changed (or reboot the system).

Getting MAC address from command line

a) Go to Start -> Run (or win key   R) type "cmd" then press Enter.

b) type "getmac" at the console window. Windows will show you MAC address of all NIC (ethernet and wireless) NIC on your computer.

Spoof MAC address in Linux
To change/clone your MAC address in Linux (and most *nix system) is very easy to do. All it takes is two easy to script commands:

ifconfig eth0 down hw ether 01:02:10:B0:80:A1
ifconfig eth0 up

eth0 = enthernet 0
01:02:10:B0:80:A1 = new MAC address you want to change to.

Yes, it is very easy to change MAC address without use any third party script/application. You can change your MAC address anytime that you need.

good luck and success, do not never feel bored to increase knowledge!!!!