I attended DevConnections in Las Vegas this year (Nov 5-8, 2007) and one of my favorite sessions was titled "PowerShell for SharePoint Developers" presented by Neil Iversen who is a regular presenter at the Minnesota SharePoint User Group. I was intrigued by this topic as up to this point did not have a chance to dive into PowerShell, let alone see what it can do with SharePoint. Personally, I felt that this session delivered a fantastic overview of the types of things you can do with PowerShell.
How many times have you said to yourself "I can achieve [x] by writing some code using the SharePoint Object Model"? That number is too high for me to predict personally... Now you can enter PowerShell into your bag of tricks as anything you can do with the SharePoint Object Model you can do in PowerShell without having to create a project in Visual Studio to do it. PowerShell is a great utility and I see a lot of work being done in the PowerShell space for SharePoint in the future.
Here is a link to Neil's blog post on PowerShell for SharePoint Developers. There are many postings online about PowerShell and SharePoint, but Neil's work is a great starting point for those new to PowerShell. I hope you find it useful. Cheers. C.