Well, I hope this is constructive criticism and not offensive in any way.
Like fourm member I cannot get the image swap to work (probable script problem - I've not had the time to read the source code thoroughly yet) and your hover buttons don't work either. It looks at first glance like the mouseover images are missing, so when you place the cursor over the navigation button, the button vanishes and a small cross appears where the hover state image should be.
I also agree that you should try a margin of some description, or perhaps dump all of your page content into an 85 or 90% width table, which will allow it to resize based on the visitors screen resolution.
Now, this may seem picky, but I am colourblind and found your font/heading font/background difficult to read. I doubt I'll be alone in that since colourblindness affects a surprising amount of people.
One final point to note: you've committed the cardinal sin and used capital letters and spaces in your file names, like this:
If you want to use multiple words to identify pages, which is a good idea to help manage your site, you should separate them with an underscore and only use lower case, like_this or steves_page.htm
Now, keep in mind that all of the above concentrates on the negatives.
What I would like to add is that you have obviously done a very great deal of work and put a lot of effort into the site and, as far as its content goes, it shows. Some of the quibbles I have mentioned are minor, while some could do with addressing, but nothing can take away from the fact that your site is an excellent example of what you can acheive when you put your mind to it, and it only really needs a little bit of tweaking in the grand scheme of things. To be honest, you've done almost all of the hard work.
Very well done.
My final word of warning - this web design lark can get addictive - you have been warned...
Best of luck with it.