Microsoft TechNet has many e-books available to download for free. The topics include ASP.Net, Office, SQL Server, Windows Azure, SharePoint and other technologies. There are several white papers and community& partner content also available for free. See the following link and don’t forget to share it with colleagues and friends.

http://social.technet.microsoft.com/wiki/contents/articles/11608.e-book-gallery-for-microsoft-technologies.aspx