http://www.edn.com/article/CA200387.html
http://www.aaroncake.net/circuits/motorcon.htm
a Pulse-Width-Modulation technique with current feedback to keep the speed of cheap 12V PCB drills more constant
http://www.electronic-projects.net/Electronic-Projects/projects/pcb_drill/index.shtml
555 timer based PWM motor control project for electric fan or other DC motor
http://www.nomad.ee/micros/pwm555.html
for example an electric drill, designed for 115V AC
http://home.maine.rr.com/randylinscott/aug99.htm
simle speed controller for PC fan, based on LM317
http://www.kotinet.com/saukki/tuuletin/tuuletin2.htm
http://www.edn.com/article/CA189474.html
DC controller using push button switch.
http://www.zen22142.zen.co.uk/Circuits/Switching/dcmotor.html