Check out your national news sources, you will quickly find a link guiding you to a donation page. If you don't immediately find one, maybe the International Red Cross's site is okay for you.
If you live in Belgium, you might want to donate to Artsen Zonder Grenzen/Médecins sans Frontières. Flemings can follow this link, Walloons this one. I'm pretty sure a gift to AzG/MsF is still rather well spent. I just wired a small amount, please do so too.
People are lying out in the streets. They are desperate, many lost everything. Donate, please. Please.