Here are some things I've written about Windows PowerShell.
PowerShell introduction. What makes PowerShell different a little history.
PowerShell gotchas. Some of the things most likely to trip up a new user.
Regular expressions in PowerShell. How to do regular expression processing in PowerShell
PowerShell cookbook. How to do a few common tasks.
PowerShell Script for Reviewing Text Shown to Users. Article about how to find embarrassing mistakes in the prose displayed to software users. Source code included.
Automatic Extract and Build from Team System using PowerShell. An article about a PowerShell script by Clift Norris for extracting projects from Visual Studio Team System and building them. Source code included.
Integrating the clipboard and the command line. An article about how to use
the Get-Clipboard and Out-Clipboard
PSCX cmdlets to manipulate
Windows clipboard content from the PowerShell command line.
Readable path listings. A PowerShell one-liner for listing the items in the Windows path in a way that's easy to read.
For more information about PowerShell, you can start at the PowerShell Community web site and find links to discussion groups, blogs, etc.