http://www.raspbian.org/RaspbianDonate
Just so people are aware, to create the Raspbian autobuild cluster, so far my out-of-pocket expenses are about $2000 in equipment, another $700 for equipment on order and an on-going monthly expense of about $100 for unlimited bandwidth hosting of the Raspbian public repository. Oh, and $40 for a Raspberry Pi

I've been holding off on asking for donations because I wanted to make sure that Raspbian had enough momentum behind it to become an on-going project. I believe that threshold has been met and, although it's not a polished distribution yet, it seems to show a lot of promise of becoming one of the leading Linux distribution for the Raspberry Pi.
It would be terrific if I donations could at least partially cover expenses related to Raspbian development. It would also help me give my wife confidence that the time I spend on Raspbian is worthwhile and useful to people. She's a little skeptical and fears my "hobby" could turn into a money pit.
Finally, I can assure people that any money raised for Raspbian will indeed be applied to further development of Raspbian. Right now, the systems we are using for the autobuild cluster are barely adequate to build the Debian derived packages. It's not too hard to foresee packages that soon will be outside the capabilities of the Freescale iMX53 Quick Start Boards we're using -- something the Debian armhf team is contemplating as well. This will likely require us to purchase newer, more powerful hardware in the future to keep up with the build requirements -- something that would be nice to have funded by the community.
In any case, I just wanted to make people aware that Raspbian is now collecting donations. If you prefer to wait and see how the project evolves, that's perfectly fine. Just keep in mind that if you do start using Raspbian on a regular basis, that a donation of at least a few dollars will help ensure that development continues.
I sincerely appreciate everyone's support of the Raspbian project so far and I look forward to seeing what the future will bring us users of the Raspberry Pi.
Mike Thompson
Raspbian Project Lead