WinAVRTM (pronounced "whenever") is a suite of executable, open source software development tools for the Atmel AVR series of RISC microprocessors hosted on the Windows platform. It includes the GNU GCC compiler for C and C++.
Check out the WinAVRTM project on Sourceforge at http://sourceforge.net/projects/winavr/ for developer information. Use the navigation menu on the left to find your way around this site.
WinAVRTM contains all the tools for developing on the AVR. This includes avr-gcc (compiler), avrdude (programmer), avr-gdb (debugger), and more! WinAVR is used all over the world from hobbyists sitting in their damp basements, to schools, to commercial projects.
WinAVRTM is comprised of many open source projects. If you feel adventurous, volunteers are always welcome to help with fixing bugs, adding features, porting, writing documentation and many other tasks on a variety of projects.
Try it Out
You can try WinAVRTM out with Portable WinAVRTM, a version that doesn't require an install. And when you get hooked on WinAVRTM, you can put Portable WinAVRTM on a USB key and take it everywhere with you! School, work, the library, the dentist, and more!
Portable WinAVRTM is maintained at www.chip45.com/PortableWinAVR.