JetBrains has actually open sourced the complete IntelliJ Community Edition IDE/platform: see http://www.jetbrains.org/display/IJOS/Home and https://github.com/JetBrains/intellij-community Incredible!
Furthermore, they are working on a cross-platform C++ IDE (hopefully using Clang for parsing): http://www.jetbrains.com/objc/features/cpp.html . I can't wait for the release.
I recently started trying to learn some basic C/C++. My usual initial step in setting up an environment for a new language is to google "intellij plugin for X", so I was very disappointed to find that C/C++ is very poorly supported with respect to most other mainstream languages.
I ended up having to go with Visual Studio, which is also impressive, but there are features I miss coming from the Jetbrains world.