USBasp is a USB in-circuit programmer for Atmel AVR controllers. It simply consists of an ATMega88 or an ATMega8 and a couple of passive components. The programmer uses a firmware-only USB driver, no special USB controller is needed.
Works under multiple platforms. Linux, Mac OS X and Windows are tested.
No special controllers or smd components are needed.
Programming speed is up to 5kBytes/sec.
SCK option to support targets with low clock speed (< 1,5MHz).
Planned: serial interface to target (e.g. for debugging)