Cant you just hit save as and save it as a .html file?

I would just like to point out that the dreamweaver templates are probably not the best thing to use if you want to build a website. They do not meet up to current web standards for the main reason that they use tables instead of divs and css. If you are trying to make a page that can be transfered over and over again divs and css would be the way to do this.

Would CSS and DIV work with most of the web browsers and OS?

yes, properly constructed div/css layouts are cross-browser compatible.

I don't use dw templates myself (they are just a pain in the rear) but you should be able to create a div/css dreamweaver template.