DIY Electrical question

Hoping someone out there can help an 'electrically challenged'
do-it-yourselfer. Electricity and I don't get along but I'm very
handy. I can solder, weld, woodwork ..... I just don't understand
electrical things well.

Here is what I'm looking for;

I am running four 120 volt a.c. fans
(http://www.allelectronics.com/cgi-bi...174&type=store)two
in my hood and two in my base cabinet for the refugium. Each fan plugs
straight into timers that are set with my light cycles to keep things
cool but this isn't working out. What I would really like to do is
have them come on/off when the temperature in the hood or the cabinet
climbs over a set temperature and goes off again once it's cooled
below a set temperature.

Does anyone have simple plans to make such temperature sensors that I
can operate with the 120 volt a.c. fans. I considered a thermostat
like you have in your home for the furnace and air conditioning units
but these are 24 volts a.c. and being 'electrically challenged' makes
that conversion tough without a 'connect the dots' plan. I'm hoping
someone out there has an easy solution.

Thanks
Lawrence