To make getting started with PX4 a bit easier, we've compiled an installation video for the Windows installer. The setup instructions for Eclipse are also valid for Mac OS and Linux.
Note that toolchain means a packaged selection of individual standard software required to develop software for a platform. We do not claim to have developed our own Integrated Development Environment (IDE), we just packaged what we needed into one redistributable file. This also implies that this development environment is not just usable for the PX4 platform, but for almost any other ARM-driven micro controllers.
The video runs through all setup steps, starting with the installation of the toolchain, downloading the PX4 Firmware the first time and finishing with Eclipse setup and board flashing. The toolchain can be used to build firmware for PX4FMU, PX4IO, PX4FLOW and any other ARM7, ARM9, ARM Cortex-M3 or ARM Cortex-M4. Functionality-wise it is similar to YAGARTO or CodeSourcery. Of course the credits for this go to MSYS, ARM and all other people porting the GNU toolchain to Windows, we just wrapped everything into an installer.
Developers have the choice to either use the Eclipse IDE and build with double-clicking make targets, or to use plain Makefiles on the console and their preferred text editor. There is a SublimeText 2 project in the Firmware folder, for users preferring SublimeText.