The innovative website Craigslist  is running an online pilot program for schools and nonprofits. Your organization can list its needs, and people who are surfing Craigslist can make online donations. In order to sign up for the program, you need to provide the Craigslist folks with your tax I.D. number. Details are available here.

I haven't heard any firsthand reports from nonprofits or donors that have participated, but would be extremely interested to know how well this is working.