Canada

http://www.onematch.ca/ http://www.blood.ca/CentreApps/Internet/UW_V502_MainEngine.n...

The first site is supposed to be more current, but isn't rendering properly for me on Firefox. On the second site, Scroll to the bottom for the button to start the process.

UK

http://www.nhsbt.nhs.uk/bonemarrow/qa/index.asp#howcan

It appears that you opt-in when you donate blood. I don't see mention of an at-home swab program.

Germany

http://www.stammzellspenderdatei.de/

https://www.dkms.de/

Others

http://marrowdrives.org/bone_marrow_donor_programs.html

(Scroll down to see the partner organizations in many countries)