I noticed there didn't seem to be a topic directly covering how to use macchanger to spoof your ip. I'm sure all of you know this already, but for the sake of contributing content, and for the less adept user, here are the precise commands you need to use.
Open a terminal window, and install macchanger with sudo apt-get install macchanger
Perform a basic ifconfig to learn your current mac address.
sudo ifconfig wlan0 down
(shuts down networking service)
sudo macchanger -r wlan0
(generates random mac address)
OR
sudo macchanger -m 00:11:22:33:44:55 wlan0
(generates specific mac address)
sudo ifconfig wlan0 up
(restarts networking service)
ifconfig
(view new mac address)
If you are successful, enjoy your success. Note this doesn't make you completely anonymous, but it's among the precautions you should be aware of.