Until very recently, Greg Shields and I maintained a private discussion forum at Concentrated Technology, mainly for the benefit of our former students. We recently took the site down during a server migration because it never got a lot of traffic (and it wasn't really intended to). But I missed having any form of direct engagement with folks, and so effective immediately I'll be answering questions at http://bit.ly/AskDon. It's open to anyone, but I especially invite former students as well as readers of this blog.
You're welcome to submit anything PowerShell-related: Technical questions, comments, and so forth. I'll use your questions as inspirations for future blog articles, too, so feel free to bring the tricky stuff!
You'll also find a host of other PowerShell experts there, covering topics like Exchange, SQL Server, SharePoint, and more. Hope to see you there!