avrdude is software used to drive a hardware programmer. It was originally written to run on FreeBSD (which is where OS X came from). So it should work fine with the programmer suggested by the tutorial.
See
here for some setup instructions.
The arduino ide is probably a non-starter unless you want to port it to the Atmega8. Or you could use an Atmega 328, with some of the same components as the arduino, but then you're not building the $50 robot anymore :-)
Joe
