In Firefox 3.x you get the same result as IE 7.x and above. To me this seems like it is one of your very fist layouts so I'll go easy on you.
1. I like the fact that you did not use any tables. CSS was a great development that I think everyone should adapt (at least by now). However, you should use external linking for style sheet. It is a lot better as compared to showing all your css in every page. You can achieve this by creating a style.css file and placing your css codes (no open css tags) and using
CODE
<link rel="stylesheet" href="style.css" type="text/css" media="screen" />
2. I think the navigation is a bit too big. I once read an article that stated "always try to show your pull nav without the users having to scroll. It is more professional and makes your site more attractive."
3. Having a free download to a premium software is not allowed here on Zymic. "LimeWire Pro" in this case is considered a premium software. Unless you have authorization, which I doubt since there are only 2 companies who has them, you are not allowed to have it.
4. Why do you have soo many empty paragraph tags? If you are trying to create spacing, you can do that with css by giving it a high element.