I could point you to dozens of articles that you could find on google anyway, so i won't do that.
However, I think w3schools tutorials are pretty straightforward and decent.
I'm no expert, but I can get around in JS. It's just a little more difficult (IMO) because it's a loosely-typed language (you can assign almost anything to anything), so it's easier to screw things up, but also more flexible. It's also an OO language, but it's prototype-based (vs classical), so that's a little different too (than Java, e.g.).
Anyway, I've also heard Douglas Crockford's book is highly recommended, and I may read it myself.
Another difficulty for me is that I just don't use it often enough, so it's not always fresh in my mind.
Oh, and I do like to use things like JSFiddle so you can play around with JS snippets and include different libraries.
Good luck.
