I joined the site the day this was posted
Unfortunately, they only send payouts by paypal - that's not happening for me, but I had some correspondence with them. I can't really afford to donate all my images, but I asked if they would accept a couple every month and have my earnings go towards one of the charities. They said yes, so I posted a couple. Seems like a very nice group too.
They did say that perhaps in future payment options will change as they grow, and that I change my choice at any time.
I'm very happing to support the charities, but my portion of the earnings will go to the children's charity - at least for now