SQL Server 2008, the next release of Microsoft SQL Server, will provide a comprehensive data platform that is more secure, reliable, manageable and scalable for your mission critical applications, while enabling developers to create new applications that can store and consume any type of data on any device, and enabling all your users to make informed decisions with relevant insights. This download comes as a pre-configured VHD. This allows you to trial SQL Server 2008 CTP in a virtual environment.
Download from here.
Reference : Pinal Dave (http://blog.SQLAuthority.com)