Remove Security Warning off SSL pages on my website

I have a new website that is going live in 24 hours. The SSL was succesfully installed but everytime you click on a page that is https you get a "Security Warning" with the following message: "Do you want to view only the webpage content that was delivered securely? - This webpage contains content that will not be delivered using a secure HTTPS connection, which could compromise the security of the entire webpage" I know that the page is linking to something that is http and not https. I just don't know how to edit the code to fix. I have also heard there is a work around. I am using Zen Cart.