Here is a great story about people using Twitter to fundraise.
Twitter is a microblogging site that allows you to make posts of 140 characters or less. The attraction with Twitter is that with only 140 characters you have to get to the point really fast. The site also makes it very easy for people to follow your writing.
Also I highly recommend reading all of Beth Kanter’s blog entries that are of interest to you. A long-time blogger and social media expert, her blog is specific to nonprofit organizations.