"Beginning November 1, new AWS customers will be able to run a free Amazon EC2 Micro Instance for a year, while also leveraging a new free usage tier for Amazon S3, Amazon Elastic Block Store, Amazon Elastic Load Balancing, and AWS data transfer. AWS’s free usage tier can be used for anything you want to run in the cloud: launch new applications, test existing applications in the cloud, or simply gain hands-on experience with AWS"
You can find the details of the offer at: http://aws.amazon.com/free/
Ubuntu being arguably the most popular Amazon guest image is also available to you for free today! Get the list of Official Ubuntu images created by the Ubuntu's very own server team at
For the free offer, you will want to launch a t1.micro instance, and it seems you will want to wait till Nov 1st for registering your account (credit card needed). This is great news! If you ever wanted to play with Ubuntu server on the cloud, now is the best time to get started!
Update: The terms page mentions "Only accounts created after October 20, 2010 are eligible for the Offer"
Update2: Please read Scott's comment below, on why you will be charged 0.5$/mo if you run the standard Ubuntu image (or Amazon's own AMIs)