I'm in France, and have a French bank account, so I was simply able to write a check and mail it. In principle you should be able to send an American check the same way, but the trouble is of course that a goodly chunk of your donation would be lost through various transaction fees when they went to cash it. If they get back to you in a timely fashion and you are able to do the wire transfer, you should update this post explaining how to do it, since I'm sure you're not the only person wondering about this.