AVR Studio 4, 5 and 6 download links
To download AVR studio 4 or AVR studio 5 from Atmel.com, atmel wants you to register. Registering and waiting to receive the download link by e-mail is annoying, so here are the direct download links.
Download AVR Studio 4.19 (build 730)
Download AVR Studio 5 (5.1.208)
as5installer-stable-5.1.208-full.exe