This zip file includes the BeOS 5.0.1 Development Environment.  It contains
everything that you need to get started creating software for BeOS.

To install, unzip 'DevTools.zip' into /boot, either with Expander or with
the 'unzip DevTools.zip -d /boot' command.

It includes:

Be's Integrated Development Environment (BeIDE)
Complete BeOS headers and libraries
GNU development tools such at the GCC C/C++ complier
The Be Book API reference in HTML
Experimental development tools such as a debugger and a resource editor

for more information and sample code, visit:
http://www.be.com/developers/freeresources.html