Ohneschuh from instructables.com has build a Arduino Shield that is able to program spare ATmega328 and ATtiny85 mcu using the ISP sketch.
Beside my Arduino instructables I also use pure ATmega328 and ATtiny85 microcontrollers. To program them I normally used a breadboard and the ArduinoISP setup with an Arduino UNO or NANO. But this was not the best solution.
So I build this programmer shield in my typical stripboard layout: Only straight lines – no crossings!
AVR Programmer Shield – [Link]