Record temperature to computer via serial port

["Alex" <samalex@xxxxxxxxx>]

Hi Everyone,

With electric costs going so high, I want to start monitoring the
temperature in my home via the computer and see the best way to program
my A/C to come on and off during the day and at night.  I figure the
best way is to rig-up a temperature gauge to the computer via serial
port and write a small Linux script to take the temp and drop it into a
file with a time stamp.

Can someone suggest such a device which would give me this information?
 I assume they are floating out there, but searching Google mainly
returned outdated pages for such devices (some going back to 1999) or
just plans on how to build one.  Though I don't mind building such a
device, I've never built something like this from the component level
before.

Thanks for any suggestions or ideas on this ...

Alex