I love free things, especially books. If you are developer, then you will be interested in these. A few are ebooks from Microsoft, but at least a the others are from other good trustworthy sources, notably Karl Seguin and The DZone RefCards.
Have a look. Download at your leisure. Definitely read them
7 Freely available E-Books/Guides I found essential for .NET Programmers and Architects : Amazedsaint's .net journal