Simple circuit using a 555 timer and NPN mosfet to provide speed control for a largish motor.
The LMC555CN variant of the 555 timer I'm using supports up to 12V, meaning this circuit doesn't need to regulate the logic part of the circuit; it uses the same voltage as the motor.
The mosfet and large diode are labeled with the part number I used, so you should be able to look them up on octopart.com. Wherever I felt parts were generic, they are simply labeled with the component's value (10pF capacitor, 1k resistor).
I haven't done more than breadboard this circuit with a simple LED as output, using 3V input (since I didn't have wiring capacity handy to handle the draw of the motor). SOOO, this circuit is labeled with the 0.1 version for a reason.