Allright, what do you need? You need only a few things: A male USB cable, a little motor that has two connectors for a ground and power connection, something to use as the propellers on your fan, wire strippers, and assorted tools.
So. Take that USB cable and use wire strippers to get to the center wiring. Youll get through a layer of silver wiring and then youll see 4 different colored wires: White, Green, Red, and Black. You can hack the green and white ones off if theyre in your way. You only need the red and black ones for power (the others are for data). Strip them down like speaker wire then connect it up to your motor as shown below.
Sweet Deal. Now make sure it works by plugging that sucker into a usb port. Technically you could make a switch for this right now, but its supposed to be a fan for laptops, not a desktop. Next, find something for your propellers. You can use a multitude of items such as toys, beer bottle caps, paper, or what I used, broken pieces of a CD. I then drilled a hole with a dremel tool to let the motors rotating stub fit onto it. I used a little glue to fill in the space in between the hole and the motor then gave it a go.
Sure enough, it worked! Its nice and ghetto and actually kept me a bit cooler than normal. You might not like the ugly way its done so I encourage you to do the following:
A. Throw it in a case of some sort. Use a Radio Shack project box or something. Anything goes.
B. Add a clip for the top of your laptop to clip on. I personally wouldnt do it to my Powerbook but you Dell owners shouldnt worry one bit.
So youre done. Go out, cool off, and enjoy your entirely geeked-out fan.