It's a standard Google Adsense block. To place it on the right, you need to modify main_posts_cell template and put there the same kind of table as I provided in my reply above (similar issue explained).
Yes I know Paul. I just wanted to know the clickthrough rate of that ad unit. I had great success with such tower units on my website but I never tried it in the forums as it appears out of the reader's vision. I mean readers usually tend to go with the flow of the text and as that unit falls outside of the text flow, I was curious to know.