Since some times their is a discussion on what's new in SQL Server 2008, when the reference material will be available!! Here is an answer to this, Microsoft has introduce a course at its E-Learning, the course aims to educate IT Professional who has prior experience working with SQL Server. Microsoft has made learning SQL Server 2008 easy by offering e-learning course, the course is devided into three category:
more details on this course is available here, all you need to have is a Windows Live Account https://www.microsoftelearning.com/eLearning/offerDetail.aspx?offerPriceId=139087