This site is asking for my credit card but I don't see any SSL or VeriSign insignia. I want to support this cause but I never provide a credit card on a non-secured site, am I being paranoid or misunderstanding something here?
Good catch. While the site isn't served over SSL, the actual Wufoo form is. And Stripe (who we're using to process the payments) only allows payments over SSL (https://stripe.com/help/ssl) so your information is safe.
Thanks for the clarification!
Admirable, but this doesn't really help the scenario where the outer page is intercepted and modified to serve a different iframe. (This is a common attack on pages that e.g. serve login forms over http, even though the form submits to https. Just change the form in-flight.)
If you inspect the source, you'll see that the form where you enter your credit card is an https site in an iframe. That will protect you against a passive MITM attack, which is what most people worry about when submitting credit cards to a website.