If it is a gift and the value is fairly low (under $100, I think, but don't quote me on that) you can just drop it in the mail as long as you clearly mark what it is on the front of the package. If it is a gift rather than a purchase mark "Gift" on the front as well.
The package will always get there even if it does turn out to be something requiring customs processing, it's just that Canada Post will intercept it and the recepient will probably have to drive out to the nearest customs office to pick it up and either pay duties or clarify what the contents are.
"Computer Software" is always a good description
