This book has become one of my most used resources. If you are looking for a way to use WMI and WBEM to inexpensively manage a Windows environment, this is it.
This book will guide you through the steps to understand and maximize the capabilities of WMI, which IS FREE.
It's really a minimal cost when you consider that it opens up an understanding that could possibly alleviate the need for one or two of your third party management products (which are costing you a fortune).
Anyway, I really enjoyed it. I have been waiting for some more information than is offered on the MSFT site, and this book gave me what I needed, and more...