do you want an on-line one? or a "hands on" course in your local area? or
would you prefer a recommendation for books that you could work through to
learn about functions etc ...
if you're looking for a good "hands on" one i can recommend on in Perth,
Western Australia, but i'm guessing that might be a bit too far to come? as
far as books go, John Walkenback has written one on formulas called "Excel
2003 Formulas" which is definitely worth looking at.