Keith Hill has released a free E-Book about Powershell.
I am a big fan of the “Effective” series of programming books from Effective COM to Effective XML. Without trying to be too presumptuous, I wanted to capture some of the tidbits I have picked up over the last couple of years using Windows PowerShell interactively and writing production build and test scripts. These items were written for PowerShell 1.0. Where appropriate I have added PowerShell 2.0 Update sections to discuss how the item is affected by the upcoming 2.0 release. As a final note, a number of the PowerShell code snippets shown use functionality from the PowerShell Community Extensions which can be downloaded from http://www.codeplex.com/PowerShellCX.
Grab your copy here: http://keithhill.spaces.live.com/blog/