Temperature sensor for mac mini?!

["noel_pilot" <HA@xxxxxxxxxxxxxxxxxx>]

Hi all,
Hoping to pick up a mac mini shortly to become the server for the
house with indigo for x10 ha control.  One thing I'm thinking that it
could also solve is my cooling issues within node 0.  Im thinking of a
bathroom extractor fan but due to noise I only want it on when
temperature inside node 0 reaches a certain level.  So....how could I
go about getting temperature into the mac mini to be usable by indigo?
I know there's lots of talk about one wire but I don't have any
understanding of how that gets onto a computer apart from something
with I/O ports like homevision (think thats right from memory?!)

Any tips or pointers gratefully appreciated.

Thanks

Noel
p.s. tivo still available if anyone wants it!