IAR Embedded Workbench for Atmel AVR - Library Source is developed by IAR Systems. The most popular versions of this product among our users are: 6.5, 6.6, 6.7, 6.8 and 7.1. The product will soon be reviewed by our informers.
You can check Atmel Studio, GrabCAD Workbench, AVR BAttery Studio and other related programs like KamPROG for AVR at the "download" section.