[Edit: Thanks for all of the interest -- the review period is now closed.]
We're getting close to "content complete" of Windows PowerShell: The Definitive Guide. The next step is technical review, where we look for both high-level and low-level feedback on the content and structure.
Also, this is a book focused on administrators. While PowerShell uber-hackers are always appreciated, inexperience with PowerShell is extremely valuable, as well.
If you're interested in being a Technical Reviewer of the book, please let me know and I'll forward your information to O'Reilly. Feel free to leave a comment here, or click on the mail icon in the sidebar to the right.