There is a lot of buzz around Scala these days. The language is now known to divide a lot of programmers (specially ones with a Java background). To chose the side I'm on, I read the excellent book from Martin Odersky, Lex Spoon and Bill Veners : Programming in Scala. The book is really well written, it explains a lot of great things about the language, but reading without exercising is not really efficient (of course you can try the examples yourself, but as I read it in bed, it is not that easy to do).
In the meantime, I found that Martin Odersky, via coursera, gives a free course "Functional Programming Principles in Scala". I am actually attending it, and, I have to say I enjoy learning this language. I am starting to think differently when coding, I found myself really more critic regarding the side effects of my methods for example.
If you're curious about Scala or about functional programming paradigm, you should attend this course and do the assignments, it takes time but really worth it.