A number of Rotary Clubs here in the Seattle area collects donated PCs. They are rebuilt/upgraded by high-school students, and these students then go on a "mission" somewhere to set up computer (learning) labs.
So, sure old computers can have a great value. Both for the actual end user, but also as a tool in helping building both communities and pride. For the past years, these kids have gone to Antigua (before that Turkey, Slovakia, etc). A lot of work, but they also get to see another part of the world, embrace different culture and food, and (this year) some needed sun in early winter.
More to read on: http://www.sammamishrotary.org/index.cfm?display=pages&pageid=6477&sub=e
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