AVR Studio® 4 is the new professional Integrated Development Environment (IDE) for writing and debugging AVR® applications in Windows 9x/NT/2000 environments. AVR Studio 4 includes an assembler and a simulator. The following AVR development tools are also supported: ICE50, ICE40, JTAGICE, ICE200, STK500/501/502 and AVRISP. AVR Studio 4 will in the months to come be upgraded to support more tools and devices. Check this web site regularly for updates.