When i went in my pc shop this morning i was looking at the zalman coolers and the chap was saying that if the fan speed is turned up they are excellent for lowering cpu temperatures? Also are they best fitted with the thermal grease that comes with them or is it better to buy one of the little pads?
It's probably best to remove the motherboard fully to work on it.
If you're buying any cooler make sure that it will fit your board. My board has 4 holes around the CPU, which bolts go though to screw the heatsink into place, not all board have these holes, so check your board supports it first. The Zalman site/coolers clearly state if you need the holes.