I was just reading an article by Duncan Riley at the Blog Herald discussing the benefits of inline ads.
Inline Ads are those placed directly within the content section of the page (often as a rectangle block).
According to Duncan Riley, if you want to increase your Adsense click thrus and therefore revenue, and are not shy about ad placement, inline is the way to go.
He gives examples of http://lockergnome.net/ and http://www.livingroom.org.au/photolog/ as sites that use this ad placement strategy.
When it comes to coding the ad placement, Duncan suggests using float div tags. See the example he provides below -
<div style="float: right; padding: 0px; margin: 0px; border-width: 0px 0px 10px 5px; border-style: solid; border-color: White; background-color: white"> ADSENSE CODE HERE </div>
This HTML code will place the adsense ad in the right corner of the article or blog in which you are pasting it.
If you look in the top corner of this post you can see an example of this code. However I have modified it slightly by adding two extra parameters - width:200px and word-wrap: normal
You will notice, particularly with the Photolog website mentioned above, that the colors used make the advertisement blend into the article so that it actually looks like it is part of the article or content. I personally don't like the photolog site because the ratio of ads to content is too high. However, it does appear to be a site that is making good money.