the Speedster

The Speedster Fan Speed Control | Fan Accessories

works great i have one. All you gotta do is plun in the fan to the control, then plug the control in.

Edit: Actually that might not work for your type.
dusto2k3 Reviewed by dusto2k3 on . fan/speed controller i have a 600CFM cage fan, its blows way too much air and is noisy as hell, is there a easy way to make one of perhaps even something i can buy fully working out the box? i read a few times due to the wire wrapping in the motor that a controller can eventually render the fan uselss, anyone have experience with these? its sounds like a tornado when plugged in and thats just isnt going to work at all. Rating: 5