ShitTalk.net has posted a guide on ARP spoofing. Here's a short quote:
"As the ARP tables can be changed to suit us, we want to change the MAC address which the manufacturer of the router has assigned to us. By changing this, our actions can not EASILY be traced, so if you visited a website, they found out that you are visiting the forums they can trace you back to you.." Read more at Shittalk
Anonymity guide: ARP spoofing
