How should I use SSL?

I'm kind of new to SSL, HostGator has gone ahead and set it all up for me.

Let me get this strait?

- User comes to http://www.mysite.com
- Adds stuff to cart, clicks checkout
- checkout link directs to https://www.mysite.com/checkout.html
- checkout.html POSTs to a credit card processor, this traffic is automatically encrypted?

Is that about it?

THANKS for your assistance, dear internet!

The way I understand it, the only way the POST data will be encrypted is if you post to an https page. So when a user submits the checkout form, the would be brought to the payment processors site and leave your site.