This is a reply of mine to a similar question. Hope it helps.
Didn't read any of the other replys, so prob repeating here, but u can use a mobile charger, or a computer power supply. Charger...is it 9v? i dunno... I've used comp power supply b4. If u wanna do that.......ahhh fuck. from memory u'll need to get the big like 20 wire connector, and with that one snip a black wire and connect it to a green one. Now u dun need a mother board to run the fans. Then with ya fans ignore the yellow wire i think ... If u want a 5 volt fan i.e a lower power fan and quieter, hook up the red wire from the fan to red wire from power supply, and black from fan to back from power supply. If u want 12 volt i.e bbrrrrrr, hook up red wire from the fan to yellow on the power supply and black to black. I'm slightly fucked right now...so i'm only pretty sure. I'm know u can search this...DIY section or som'n.
Intake or exhaust is controlled simply by which direction you point it...not wiring ofcourse...