(Getting a lot of questions on this recently, so I thought I would throw up a quick blog post to direct people to.)
If you want to test out having users "Pin" content from your email on Pinterest, here is how to build the url that will sit behind the "Pin it" button:
We'll create a Pin of my guitar as an example. First, grab the url you would like the Pin to go when clicked:
Next you'll need the url of the hosted image you would like Pinned:
And Finally, you'll need the description you want to go on your pin:
And Viola! You have your link.
Here is the link in action. Pin me.