Help! how to built my own incubator???

i been debating whether to buy an incubator or build my own....
and i think i'll rather build my own and save some money. anyone know where i can find a good tutorial of how to build my own incubator???

Cooler

http://www.eyehit.com/degei/supportf.../inc/index.htm

Fridge

http://www.arbreptiles.com/cages/incubator.shtml

DIY section is loaded with.. Well.. DIY projects including Incubators. :D

It depends on how many clutches you plan to hold but what i am doing is the cooler incubator with a high watt submersible water heater. Holds 4+ clutches and holds temps and humidity perfectly. $200 with Herpstat.