How do I manage multiple AWS accounts?

You can easily and simply set up each AWS account that you want to manage from the Accounts tab. Once you add an account, switching is as easy as selecting the account in the list of accounts at the top right of each page. Also the last account used will be remembered, and next time you log in o Ylastic, you will automatically be using that account.

http://blog.ylastic.com/managing-multiple-aws-accounts