There’s a new kid in town, the AWS Management Pack for SCOM 2012. The AWS site details the steps quite well which you need to get the service up and running which can be found here – http://docs.aws.amazon.com/AWSEC2/latest/WindowsGuide/AWSManagementPack.html
Here is an example of the kind of information you can get out of this management pack;
EBS Volumes view
EC2 Instances view including detailed information
Download, install and get monitoring!