Arduino ISP (In System Programming) and stand-alone circuits

We use an Arduino to program other ATmega without bootloader . This technique allows you to use all flash memory for code and make boards using new ATmega, cheaper than those with bootloader.

http://www.open-electronics.org/arduino-isp-in-system-programming-and-stand-alone-circuits/?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+OpenElectronics+%28Open+Electronics%29&utm_content=Google+Reader