Powershell in a Month of Lunches is a great book to get started with. Don Jones really understands adult learning, so he can really keep you engaged.
I like to mix some more formal training at first with a project in mind. As soon as you learn something in your training, apply it in your project. And then when you are done with the training, continue researching in order to complete the rest of your project goals.
Powershell is interesting because you can make scripts without having a clue what an object is, but understanding about objects is fundamental to learning powershell, so I really would recommend starting with some kind of training rather than just trying to create a script.