I am using dreamweaver 8 and I have a couple of websites but when my partner views them on his 800x600 resolution screen - the page looks all to the right hand side.

So how do you optimize a page for 800X600?

i optimize my website in a 800x600 screen resolution, and i center it in the browser page.

If you want to make a 800x600 page.. make ur site less than 800pixel,

my site is using a 768 width pixel.. so if my page stretches, it will still look nice on 800x600 screen. Just make it less than 800 pixel width. some times it stretches 1-10 pixel.. due to some content.. etc.

There are several ways to make a site optimized for 800x600 and larger.
You can make a fixed width page with a max width of 780px and center it, OR you can create a fluid layout that uses percentages to work well at narrower screen resolutions and wider resolutions. Fixed width is a bit easier to do, fluid takes more work.