New tools for non-profits from Google, as announced on the Official Google Blog:
http://googleblog.blogspot.com/2008/03/google-for-non-profits.html
The quote from their blog entry on how you can use the tools seems to fit most library's needs, particularly the online donations:

• "When you're writing a grant application, don't get stuck emailing drafts back and forth. Try Google Docs to collaborate on documents with your colleagues.

• Cut costs and save time with Google-hosted email at your own domain. Access your e-mail from any computer with an Internet connection.

• Accept online donations without hassle and with no transaction fees until 2009 with Google Checkout.

• Apply for free online advertising through our Google Grants program to raise awareness and drive traffic to your website.
  

• Start a blog to keep your supporters informed and engaged."