I have toyed around with some different placements and colors with ads and have not found any large changes in click ratio, check out my site and let me know what could be done to possibly improve my ratio. Since 10/1/06 I have a ratio of 1.81%. http://www.asteriskblog.com Let me know. Thanks!
I had link boxes underneath the titles of the posts, but not only did it look pretty ugly, I got very few clicks from it. Also after I added those to the page, my pay per click reduced by about a dollar. When I had just the header and one other ad block on there, I was making anywhere from $1 to $3 per click, however after the link boxes were added it reduced down to almost $0.30 per click. I didn't much care for that.