No idea? I'm not sure how it's done on other site, wether it's manual or automatic but I have seen a few site with a hosting donations section with a Target and current amount, but like I said it's probably updated manually rather than automagically.
It would be cool if we could though, then we could see where we stand all year round and not have to scrabble around at the end of the 12months. Although I bet no one would chip in till the last minute then either :P