I think the "About the Author" section could go at the end of the About page.
The unused space in the side-bar troubles me. I'm having a few thoughts about it and related topics:
1. The requirements are something that the user should be aware of before downloading. In addition to listing them in the side-bar, maybe it would make sense to duplicate the requirements section from the about page on the download page. Have a sub-section on the Downloads page for "Requirements" with introductory text like "Before downloading, make sure your system can fulfill these requirements." We can leave the requirements summary in the side-bar too (like you already do), but I just had that thought while looking at it.
2. It would be nice if the screenshots were more prominent. Since they form a relatively narrow list, do you think it would make sense to put the screenshots in the side-bar, to give the side-bar some more purpose?
3. In my version of the site, I actually have a file called NavBar.inc which is included in all the other html files. They're actually .shtml files so that I don't have to maintain the navigation links independently on each page. Would it be practical to do the same with these pages to include a common navigation bar, and possibly the portion of the the side-bar that doesn't change? Details of all the formats supported by SourceForge are at https://sourceforge.net/apps/trac/sourceforge/wiki/Project%20web%20and%20developer%20web%20platform
. Details about shtml format are at http://en.wikipedia.org/wiki/Server_Side_Includes
. If you don't have a way to test .shtml files, I can probably implement that part myself.
4. Now that the "About" information has its own page, I don't think I need the "Important Information" heading. The sub-headings by themselves will suffice. I can change that just as easily as you, though (after I get the site).
5. Do you happen to know a good way to automatically include RSS feed/links on a page? Then I could just have the RSS feed instead of manually adding news links, right?
Also, I just noticed that the bold formatting of the text at the beginning of most of the news items was lost.