Yes, I have been building all my sites (over 40)to 800x600 and centering.That's fine but I always dreamed of a system where I could buid to that yet it would fill and look right in 1024x768 or 1280x1024.
Recently a member of a club I do took over the club site and used many of the same elements I had used but the site automatically resolves to the screen size!!!!I have tested it at http://www.coastastronomy.ca/ and it agrees with my vision. The text takes up fewer lines and spreads across the page - the graphics re-size. I contacted the club member and his answer was 'that he was just using html' and he sounded puzzled by my query.
The site doing this is http://www.coastastronomy.ca/
Anyone have an explanation and a way SiteSpinner might do this?

See the tutorial on "Page Centering and Sizing", and look particularly at the relative positioning and sizing example.

The fly in the ointment in this example is that SiteSpinner uses CSS positioning to control object positioning. Consequently if you have even a single object fixed on the page by CSS, and other objects free to move, you can get overlaps.

A possible solution is to turn CSS positioning off for everything (setting in Project Options > More button). Try it on the tutorials index page. For pages like this, Z-order becomes very important, and also you will probably need to use tables for horizontal positioning.

This will need experimentation -- which I haven't done! If you get something that works, please let's know.

I had read about this years ago and gave up after experimenting some back then. Just now I took your advice and after opening the Tutorial page changed it to No CSS and Centre to see what I got after posting. A mess! Centred the listings went down the page in a narrow column about 20 pixels wide. Without centering all the text is jammed to the left. There is sure no expansion fo text boxes.
Doing scores of sites and 100s of pages why would I even entertain the effort of trying to master this. Seems to me that this something that the developers should tackle and then I would volunteer and addon or upgrade fee.
What it says is that the CSS postioning system is, in some ways, inferior to plain old html. Not a good thing. On the other hand SiteSpinner has been and is a wonderful tool for me so I think I better shut up now.