Hey, I was trying to set fuses for atmega8 that it could work with external crystal 16mhz. But i didn't find any easy tutorial or information how to do it. I am using avrdude to programm atmega but i don't know how to make it work with that oscilator. Could you help me?
Have you seen http://www.engbedded.com/fusecalc/?
Yes 
but i am just a beginner so it's a bit difficult to understand what to select i want 16mhz external crystal. but i don't know whitch one is it.
If you can program it with a programmer, why not use the Arduino IDE ?
Select Arduino NG with ATmega8. That is for a exernal 16MHz X-tal.
If you program the bootloader, the Arduino IDE will also set the fuses.
After that you can use the RX and TX to upload the sketch, or you can use the Arduino IDE to upload the sketch with the programmer.
Also you can take a look of the datasheet to understand what fuses registers means and which you need to modify.
thank you very much 
i programmed atmega suscessfully 
datasheet really helped a lot