I've been experimenting with the 'software' USB driver from obdev.at and it looks really great to be able to have a packet based communication with the host, and get rid of the serial cables.
Their newer version supports 16Mhz and I've been using that on a Mega644. Problem I have is that the device is not recognized on my linux box all the time. Works fine when I plug it into the Mac, but not on this debian box..
I tried hub/no hub, changed the cable etc.. no luck..
Anyone else is using avr-usb ?
I'm using this circuit, on prototype board:
And the rather heavily reworked board :D