The bottom part of the page looks fairly terrible. It's just a series of horizontal lines with stuff in the middle of it, centered. Perhaps some actual layout would be appropriate.
Example of what I see:
http://img175.imageshack.us/img175/4391/20500013ry2.png
I mean, that digg button is ridiculous. Move it up into the content, where people can see it. Half the stuff at the bottom there should either be integrated with the rest of the page or eliminated entirely. Honestly, it should be integrated into each post, so that each post can be dugg separately instead of digging the site as a whole.
The Google Custom Search box in the upper right is broken on the "Scrum Blog" page.
The Forum frame is too narrow.
The Amazon A-Store on the Books page looks funky. Perhaps some better integration is called for.
Most of the non-blog pages appear to be implemented with static.html files. While there's nothing wrong with that, using the WordPress Page functionality for these might be preferable and would put everything into one easy management tool. Use of Page Templates would be handy for the custom work like the frames and the contact form and such.