Question : recurring billing

What is the easiest to use and fastest to setup website to handle recurring billing to receive monthly donations for a non-for-profit agency?

Answer : recurring billing

paypal is one option but they charge 2.2-2.9% per-transaction fee.
check this site for some ideas:
http://www.lincproject.org/toolkit/techtips/tt_onlinedonation_072005.shtml