How to sign up for preview features?

Windows Azure “spring release” 2012 provides few new features: like media service, virtual machine (with real persistence), and Web Sites.

Media Services

Windows Azure Media Services enable solution providers and content owners to build end-to-end workflows for the creation, management, and distribution of media. Combining core components of the Microsoft Media Platform, Media Services include Encoding, Format Conversion, Content Protection, On-Demand Streaming, and Live Streaming. Solutions built on Media Services offer the flexibility, scalability, and reliability to deliver high quality media experiences to a global audience.

Virtual Machines & Virtual Networks

Easily deploy and run Windows Server and Linux virtual machines in Windows Azure. Windows Azure Virtual Machines allow you to migrate applications and infrastructure without having to change existing code. You can also create your own virtual private networks (VPNs) in Windows Azure and securely connect them to on-premises IT infrastructure with Windows Azure Virtual Network. You can extend your on-premises networks into the cloud with control over network topology, including configuration of IP addresses and DNS.

Web Sites (also called Web Site as a Service)

Quickly and easily deploy sites to a highly scalable cloud environment with the frameworks and open source apps of your choice using Windows Azure Web Sites. Get started for free and scale as you go on a cloud platform that enables automatic scale-out options across shared and reserved instances for greater isolation and performance.

If you like to take a look on the preview: https://account.windowsazure.com/PreviewFeatures