I have added a groupboard page. I set up a free board at http://www.groupboard.com/demo/gbregister.shtml
I put the iframe code in Mori's Code Wrapper gadget.
Insert, More gadgets, search for Code Wrapper.
I set it to 100% wide and 1500 pixels high.
On a sub page I inserted the admin code they sent to me in an email after I registered.
See Groupboard page here.