Free eBook on Windows Azure
I just found a free 96 pages eBook available from Eric Nelson about the windows azure platform. Looked through it very quickly and I thought it would be a very good book to learn the overall of Windows Azure, SQL Azure and the software architecture which will be deployed on Azure. You can download it here.
You can also read the book Cloud Computing with Windows Azure Platform by Roger Jennings online from here. Remember this is just the online version, so you cannot download or print this.