Use http://www.clickandpledge.com/
They are SO AWESOME. Give them a call and they will give you a demo where they take over your computer screen and walk you through the set up. They dont charge ANYTHING they just take a small (very small) portion of the donation. But so does paypal, and it's much larger. This company also has free giveaways (like ipods cameras etc) for people that donate to YOUR CAUSE.. please give them a call.. they are so nice!!