This is great news. We have just started using EC2 and S3 for a startup I've invested in and one of our concerns has been using mysql as it needs to be used on an EC2 instance. We've been looking at ways to ensure our data is safe, but this SimpleDB could provide the answer we've been looking for. Hope I get into the beta! Out of interest, anyone else out there using mysql on EC2 and how have you dealt with ensuring your data is safe?