Based on HIDKeys of V-USB, which is for Atmel ATmega8.
Current master branch is configured for AT90S2313 which is actually discontinued product. The code is almost same as original code but changed number of keys, IO ports etc. Also added a project for AVR Studio 4 with WinAVR. I'm using them on VMware fusion but we may able to use similar tools like CrossPack for AVR Development.