Ive just built one of the temp controllers in that heatsink-guide tutorial, and have to say its pretty cool
Especially since its only about £2!.
Quick tip tho, dont use it with papsts! when the voltage is just below the startup voltage they tick like crazy! I think its the same as that bearing tick you sometimes hear with papsts except its much louder! Im gonna have to try it on a panaflo...
on the plus side i did find that my CPU can run passively cooled when im just surfing and listening to mp3s! This is a P4 1.8A @ 2.4Ghz, using an Alpha 8942T heatsink, rises to about 48C then stabilises there!