Hello Alan,

I am sorry for the late reply.
If I understand you correctly, you're the administrator of the site and you want to edit a blogpost created by another user/author. But the issue here is that the radio button for "Contribute entry to" is not there eventhough you're the admin.
Actually, the radio button "Contribute entry to" will be visibled depending on the author of the blogpost. The author must be a member of a team group in order to show the radio button. I have made a test on one of your blogpost titled: "Spotlight On: The Misadventures of Salem Hyde" and now as you can see in this screenshot: http://screencast.com/t/GeOEiUNsMaWY Instead of Rebecca (Original author), I have change the author to "Stack Ideas" which the member of the Pagan News Beagle group and the radio button "Contribute entry to" is now visible.

Hope this will help.
Thanks.