If you have the slightest interest in PowerShell, and you’re keen on learning more about it, I strongly recommend you download this book:

Mastering PowerShell (from PowerShell.com and written by Dr. Tobias Weltner)

It is an awesome, well written 567 page book that covers PowerShell through and through. Here are the chapters:

1. The PowerShell Console
2. Interactive PowerShell
3. Variables
4. Arrays and Hashtables
5. The PowerShell Pipeline
6. Using Objects
7. Conditions
8. Loops
9. Functions
10. Scripts
11. Finding and Avoiding Errors
12. Command Discovery and Scriptblocks
13. Text and Regular Expressions
14. XML
15. The File System
16. The Registry
17. Processes, Services, Event Logs
18. Windows Management Instrumentation
19. User Management
20. Your Own Cmdlets and Extensions

Thanks PowerShell.com!