Computer fans are really simple to wire. There generally have anywhere from 2-3 wires. Red is for 12v and black is the ground wire. If you have a yellow wire just tape the end so it dosn't short out, it is used by computers to determine the fan speed. Go to a local thrift store or radio shack and get a 12v DC wall adapter. like this:


then cut the end off and attach the wires, you need to attach the red to the 12v side which I believe should have a white stripe on it. If you can't figure out which is 12v try both ways it will not do any damage, if you want to be safe you could get someone to help you with a multimeter. Also you can try smaller voltage power adapters if you want the fan to spin slower.

As for heat tape I would use 1-2 feet of 11" on the back. I use 4ft of 11" to heat a large (12 or more clutches can easily fit) coke fridge incubator and it works well, the amount of heat tape in the picture shown by tideguyinva is a bit overkill but as long as the thermostat is good there will not be any problems. It may heat up too fast for a on/off style thermostat unless you wire in a dimmer.

You should have 10-15 watt's of heating per cubic foot of space, Roy Stockwell a well known and respected hobbiest here in canada gave those numbers he is known for building incubators. If you go by that you should be ok with 2 ft of 11" flexwatt (40w)

I hope these tips help.

Richard