Now this is exactly what I was wanting for my AWS EC2 based projects:
We are pleased to announce that it’s now even easier to use Auto Scaling to manage your Amazon EC2 capacity and maintain availability of your applications. Starting today, you can use the AWS Management Console to create and update Auto Scaling groups and launch configurations.
In the console, you can create an Auto Scaling group based on a template that you define for your instances. You specify the number of instances you want to run and Auto Scaling will launch the instances for you, keeping them balanced across Availability Zones and replacing unhealthy ones.
You can also create scaling policies that adjust your group size dynamically in response to Amazon CloudWatch metrics, such as average CPU utilization. Even if your application only requires a single instance, using Auto Scaling can help you keep it available by replacing the instance if it fails status checks.
For more information, see Get Started with Auto Scaling Using the Console in the Auto Scaling Developer Guide.
Time to go and experiment.