Ultra Low Power LED Flasher using the Padauk PFS154 – Tim's Blog
Fairchild Semiconductor's New Low-Power LED Drivers with Integrated MOSFETs Help Designers Reduce Board Space and Design Times — LED professional - LED Lighting Technology, Application Magazine
High Power LED Driver Circuits : 12 Steps (with Pictures) - Instructables
2-Year Ultra Low-Power LED Flasher : 11 Steps - Instructables
low power - simple, energy efficient circuit to make single IR LED blink - Electrical Engineering Stack Exchange