Well I just tried to place an order and the site STILL isn't secure, some three and a half years after this post. Why in the world don't they have a secure server? Weird.
Having a secure server (HTTPS / SSL) is really more of a case of perceived security than real security. It makes customers more comfortable, but the fact remains that data theft is extremely unlikely in-transit. It's far more likely that a server would be compromised, or that your card might be double-swiped in retail. I would not let lack of a secure connection impede making such a purchase except in rare circumstances. (i.e., public, unencrypted wi-fi in a coffee shop). Please, do go ahead and purchase!
And after typing all that, I went to look at the site - the checkout process is secure, but in a frame, so you don't see "https://" in the URL. Yahoo!'s small business 'stores' service handles the information-collection process.
That said, PB & Co.'s products are exceptional. I found them on the shelves of my local Giant and snapped them up. I thought them expensive at the time, but having checked the site, they weren't charging more than direct - just no shipping!