Just a quick note on donating old computers. I was looking around for somewhere to donate my old desktop, and called the David Suzuki Foundation. They’re happy to take it, and will issue a tax receipt for the value of the machine.
I’m sure there are dozens of other like-minded non-profits, as well as agencies dedicated to recycling computers for charitable purposes.
DarrenBarefoot.com 
Computers For Schools!
http://cfs-ope.ic.gc.ca/default.asp?lang=en&id=6
The BC Main office is located on Douglas Rd in Burnaby and will take P3 computers or better, I believe.
The Vancouver Community Network is usually happy to take computer donations.
Techsoup has a list of recyclers. It includes some in Canada. The search facility is, uh, not really that good. But, then again, I don’t run the show over there anymore.
good idea.
Is there something you need to do to make sure people can’t read things off your old computer?
Lisa: I only know of one product–CyberCide. There’s probably others, but that’s the one I plan to use unless somebody suggests something better.