Use the latest IntelliJ IDEA release and install the Scala plugin from within the IDE.
 
 Compilation withing IDEA is performed in "-Dlocker.skip=1" mode: the sources are built
 directly using the STARR compiler.
 
 The following steps are required to use IntelliJ IDEA on Scala trunk
  - Run "ant init". This will download some JARs from to ./build/deps, which are
    included in IntelliJ's classpath.
  - Run src/intellij/setup.sh
  - Open ./src/intellij/scala-lang.ipr in IntelliJ
  - File, Project Settings, Project, SDK. Create an SDK entry named "1.6" containing the
    java 1.6 SDK