I ran across a couple of good links for free e-books about Microsoft SQL Server and figured I should share them.  

Introducing SQL Server 2008 by Peter Debetta, Greg Low, and Mark Whitehorn.  You can learn about the new features SQL Server 2008 including Security and Administration, Performance, Type System, Programability, Storage, High Availability, and Business Intelligence.  

Brad's Sure Guide to SQL Server 2008 by Brad McGehee.   This is about SQL Server 2008 and also includes two of his other books:  How to become an exceptional DBA and DBA Best Practices.  

Mastering SQL Server Profiler by Brad McGehee.  As its name implies, learning all about SQL Server Profiler (2005) and how it can help you make your systems faster.  

Dissecting SQL Server Execution Plans by Grant Fritchey.  Hey, this is an awesome book that talks about how you can read the excution plans and make your system go faster....hey who wouldn't want that?

Hopefully you will find these helpful.   

Also, if you know of any others, please let me know.