Easiest way to distribute for free is on somewhere like freecycle.
There are plenty of people who do exactly that on freecycle, although not too sure about the Linux side of things.
Most "refurbished" computers are offered with no license, or no software.
I do know someone in Wrexham was pre-installing Windows as an OEM installer (not sure how), so people could just type in their product key when they turned it on.
As for getting hold of hardware, you could just ask on freecycle (i.e. tell people you are recycling), or approach corporate users who often bin perfectly usable stuff. Unfortunately, the latter will often remove HDs for data security reasons before donating though. Only way to persuade otherwise is to offer military grade data wiping service (which they may even pay you for!)
Freecycle: http://uk.freecycle.org/