When I speak at conferences or during a training class, I inevitably give attendees and students a list of resources that I feel can help them continue to learn and master Windows PowerShell. I'm assuming other beginners who haven't been to one of my conference sessions or training classes would find this useful information.
Books
I have a Books and Training page so I won't spend too much time talking about my own books. Certainly for someone just getting started, pick up a copy of Learn Windows PowerShell in a Month of Lunches. Once you've gone through that then go through Learn Windows PowerShell Scripting in a Month of Lunches. Those are the 2 titles I would consider essential. At some point after completing the first Lunches book, you should get a copy of The PowerShell Practice Primer and work through the 100 exercises. Once you have those fundamentals I'd recommend the PowerShell Scripting and Toolmaking book that Don Jones and I published at Leanpub.com
After that, get a copy of The Windows PowerShell Cookbook by Lee Holmes. This is a fantastic resource on all the things you can do with PowerShell. I think once you have a foundation in PowerShell you will get more out of it.
The other reference book I would recommend as essential is PowerShell in Depth: An Administrator's Guide. This book covers everything in PowerShell that an IT Pro would need to know in order to understand the language, syntax, and shell.
If you work your way through these books you will have learned a lot about PowerShell and will no longer be a beginner.
Online
There are hundreds of online resources for PowerShell from sites to blogs to RSS feeds. Here are a few that I think you should be aware of if you are just getting started.
PowerShell.org is THE place for all your PowerShell needs. This site is operated by a non-profit organization devoted to promoting PowerShell. The organization runs The PowerShell +DevOps Global Summit, events I encourage you to participate in. But most importantly are the site's forums. If you are stuck on a PowerShell problem, this is the place to go. The forum is closely monitored by PowerShell MVPs and community leaders. It is extremely rare that a question goes unanswered.
You should keep up with the official Microsoft PowerShell landing page.
For you social media types, there is a pipeline full of information on Twitter. Start by creating a filter for #PowerShell. I also hope you'll find it worthwhile to follow me. There is also a PowerShell Facebook page.
I've created my own page with tips, tricks, and advice that I typically share with my students and conference attendees. I plan on updating it frequently so be sure to bookmark this.
Blogs
There is no shortage of blogs these days. While I typically rely on Twitter mentions to know what I should go read, these are some blogs that I think are worth your time subscribing to. These authors consistently put out quality content that I think you will find useful. At the very least, I encourage you to use the content aggregator at PlanetPowerShell and definitely stay connected to the PowerShell Community Blog.
Video
There is a lot of PowerShell related content on YouTube. You can start with my channel. But I especially recommend the channel from Don Jones.
In years past I did a lot of video course development for TrainSignal which is now part of Pluralsight. Your best bet is to search their course catalog for PowerShell content. You'll see my courses. I'd say anything with the term "Essentials" or "Fundamentals" is fair game.
Learn It Every Day
But the most essential thing you can do to learn PowerShell is to use it every day. When a task comes along, see if you can figure out how to accomplish it with PowerShell. At the very least try to read something new about PowerShell every day. To help, here are two PowerShell commands you should run daily.
Get-Command -Module Microsoft*,Cim*,PS* | Get-Random | Get-Help -ShowWindow
Get-Random -input (Get-Help about*) | Get-Help -ShowWindow
The first command will pick a random cmdlet from what I consider the basic, out-of-the-box PowerShell set of commands, and display the help for that cmdlet in a popup window. The second command does a similar thing for one of the conceptual about_* topics.
There are many, many more resources I could recommend to learn PowerShell but I wanted to limit this page to those a beginner would find the most useful.
Good Luck!