Yes, that's all you need.
Write your program in CodeVisionAVR, AVR Studio, or whatever else... when you compile it, make it output a .HEX file. Then use pony programmer available for free at to load the .HEX file onto the ATmega8.
I use an extremely similar programmer, only difference is mine hooks up to the serial port. I use it with AVR Studio and pony programmer for ATMega8's... works like a charm. Just don't forget to power up the chip when you program it. :wink: