So what's the best IDE?
If you're an eclipse user, it's Scala IDE (http://scala-ide.org/). You can find a full download eclipse + Scala IDE plugins on the typesafe homepage (http://typesafe.com/stack/scala_ide_download).
If you're an IntelliJ user like myself you just need to install the Scala plugin.
Both IDE's have there drawbacks, none is perfect. I guess the easiest way to start is using the Scala IDE.
Just as a side note, this is not a 'learn Scala' class. This is learning functional programming using Scala as the functional language. So, you won't get a lot of info on how Scala's complex type system works. But, this would be a great class if you are not familiar with functional languages (or what functional means). The functional aspect is very easily transferrable to other functional languages as the application is very close in all other functional languages (just as imperative OO language semantics such Java, C#, Ruby, Scala etc. are easily transferred).
It's true that this is not primarily a "learn Scala" class; we will concentrate on the purely functional subset. But types won't be omitted. We will focus on Scala's type system in week 4 of the class.
I just wanted to take this opportunity to let you know that I find the course content to be extraordinarily well designed. The lectures seem to hit all the right notes at the right moments, the homework is exercising the right muscles, and the grading does an excellent job of guiding us towards good test-driven-development and away from mutable state, etc.
If you're coming from Java, I recommend the Scala for Java Refugees[1] series of blog posts. If you're interested more in the functional side, there is a course by Odersky on Coursera right now.
I haven't found any Scala IDEs stable or enjoyable yet. I've been using [insert favorite editor] with sbt[2].
