In my case, due to having selected the "per month" option, pledges begin to get processed on the 1st of every month (they say it can take up to 72 hours), so if you just want to donate once, you can pull your pledge after that. I'd like to set up a much more convenient donation button via PayPal, but that's not terribly easy to figure out, and i'm not sure how the paypal.me thing works yet. :v