Eclipse - Eclipse is an open source community, whose projects are focused on building an open development platform comprised of extensible frameworks, tools and runtimes for building, deploying and managing software across the lifecycle.
Circuito.io - Instant code and wiring for your project
Netbeans - NetBeans IDE 7.0. Develop desktop, mobile and web applications with Java, PHP, C/C++ and more. Runs on Windows, Linux, Mac OS X and Solaris. NetBeans IDE is open-source and free.
embedXcode - embedXcode is a template for Xcode.
IntelliJ IDEA - Capable and Ergonomic IDE for JVM
B4R - Development tool for native Arduino programs.