AWS encrypting data at rest

Here is good white paper on encrypting data at rest on AWS:
http://media.amazonwebservices.com/AWS_Securing_Data_at_Rest_with_Encryption.pdf

Amazon now offers Amazon EBS native encryption: http://aws.amazon.com/about-aws/whats-new/2014/05/21/Amazon-EBS-encryption-now-available/
S3 has SSE encryption, client side encryption and SSE with key managed by you: http://aws.amazon.com/blogs/aws/s3-encryption-with-your-keys/
All data in Glacier and Redshift is automatically encrypted.

AWS RDS database encryption

There a couple of ways to encrypt you data at rest when using AWS RDS:

1. Oracle RDS TDE support : http://aws.amazon.com/about-aws/whats-new/2013/04/18/amazon-rds-oracle-encryption
2. Oracle RDS with Ciphercloud : http://www.ciphercloud.com/database-encryption-and-tokenization.aspx.  AWS specific here (and mentions HIPPA) : http://www.ciphercloud.com/aws-encryption-ciphercloud.aspx

Oracle TDE also supports encryption at the network tier.