A couple of months ago I found a story on Hackaday (and later on other places too) about programming ATtiny processors through Arduino. I thought that it would be nice to have this in a form of a shield. Now this product has become reality and it does even more than programming ATtiny processors. A collobaration between Flyton and myself resulted in a shield that makes it possible to program ATtiny45/85 processors, various Atmel ATmega processors (168/328/44/48) and it can even be used as a STK-500 programmer.
For more information see: http://flytron.com/open-source-hardw...r-arduino.html