Asterisk on Amazon Cloud


Just wondering if anyone is running Asterisk on the cloud. I set up a pretty busy system with 40 extensions which has being running for about 2 months. Everything is going pretty well apart from having some intermittent call quality problems. Just wondering if anyone else has tried it.

I am wondering whether to setup a small Asterisk server on cloud, but have no idea what the costs would arise.
Can anyone already running this kind of instance, provide the information on how much should be paid for this service ?
Please specify installation costs, running idle for a month and running busy with moderate load.