Sometimes when I am at a websites they will say "Bandwidth Donated by -----" or something similar to that (go to csszengarden.com and scroll to the bottom of the page for an example). What I am wondering is how would you donate bandwidth to someone?

I've never seen that before, but my first guess would be that they donated money that was used towards bandwidth? Or maybe the person who "donated" the bandwidth hosts some of their images or large files? I know I'm probably wrong, but this is my guess :)

I guessed they donated money but I never thought about the file hosting.
Thanks sisqoluv! :)

Yeah, I was going to say that. Either they have their blog/images hosted on that person's site, or that person pays for the hosting or extra bandwith that the site might need.

it may mean that the site is being hosted by that specific service for free for whatever reasons.