Having it stretched all over the screen doesn't mean that it doesn't fit 800x600, I suggest that you get FireFox and it's "webmaster" extension. It have a great feature saying "resize ot 800x600". My site is perfectly in 800px width, plus I just received an email from Cleo that the site is approved.
Thanks Cleo!
P.S.
That's not my second site, that's my second free site

Thanks for encouraging me, thank you all!
