Attackers are leveraging Amazon’s EC2 Infrastructure to launch attacks against VOIP providers…
http://www.voiptechchat.com/voip/538/sip-attacks-from-amazon-ec2-cloud-continue/
My main takeaway is Amazon’s laissez faire hands off approach to the use of their cloud services for nefarious/illegal activity. In the real (physical) world, if you provide the resource then you will incur some culpability if it is used illegally. I guess Amazon will have to learn this the hard way.