As part of the Google Grants program for non-profits, Google offers their Google Checkout service to qualifying non-profits at no-charge with no processing fees. Depending on the fees you would pay with a competing processor this represents an instant 3% jump in your organization's fundraising efforts just by using Google Checkout.
The only limitation has been recurring donations. To address this Google launched Google Subscriptions and now we need to get support into CiviCRM so we can enjoy a single free processing fee payment gateway.
A new Make it Happen iniative was launched to get this going in 4.1 or even 3.4 if we meet the campaign goal soon! A donation to this iniative will easily pay itself back by the savings in processing fees. This initiative is already 70% there with donations from Powered by Action and the International Mountain Bicycling Association (IMBA):
Check the forum discussion for more info: