Change Mac Address

$ ifconfig eth0 down
$ ifconfig eth0 hw ether 00:00:00:00:00:00
$ ifconfig eth0 up

or

Add the follow line to /etc/sysconfig/network-scripts/ifcfg-eth0

MACADDR=00:00:00:00:00:00

$ service network restart(or /etc/init.d/network restart)