I've been involved in the SETI@Home project for 9 years now. I've contributed hardware and LOADS of CPU time over the years. It's one of only two non-medical scientific distributed computing projects that I belong to.
S@H is using Flattr to allow people from all over the world to donate to their charitable causes and recipients of choice. I've begun using Flattr just recently in order to contribute to SETI@Home, but it also occured to me that I could use Flattr to bring a little extra revenue in to the site.
With the money donated by Flattr users, 50% will go to the Canadian Cancer Society and 50% will go to Mark McManus - the creator of MuscleHack.com. Also, you can support these worthy recipients by clicking on ads shown here that interest you as I'm also a Google AdSense publisher.
I'd recommend checking out Flattr as it seems to be taking off and it's a great way to do micro-donations to many worthy causes all at once. There's even the option to have recurring payments set-up so that you can contribute monthly to your chosen recipients.
Have a great day all!