As easy as this turned out to be and as easy as it seemed it should be, it took a little digging to find out how to really accomplish this. Since John and I both manage the blog I wanted all comment moderation requests to come to both of us rather than just to me. However, WordPress doesn’t seem to accept more than one email address in the admin notification section. It let me add both email address with a semi-colon separating them, but after saving the settings it removed the semi-colon and left the box with an invalid email address. Since our site is hosted on a cPanel server I then turned to setting up the forwarding through cPanel.
cPanel has recently updated to version 11 and introduced a much better user interface with quite a bit of error checking. For example, when I tried entering two email addresses into the forwarder address box it kindly let me know that ; or , as a separator were not acceptable. After a little research I discovered that you simply create two forwards for the same email address. One pointing from the desired forward blog@domain to my email, and another pointing again from blog@domain to John’s email. This actually creates a single forward entry within the operating system, but cPanel keeps it recorded as two separate fowards. This now also means that both John and I will be able to moderate the comments so they should show up much quicker.