Selling to Canadians

I've read about nightmares selling equipment to our neighbors north of the border and would like to have some guidance on how best to handle such a transaction. Is there an exchange rate issue? Also, what's the best way to ship (cables) -- and how are the duties handled? Is it a percentage of the sale price and, if so, do they go by the price new or the resale price? Thanks a lot for your help.