First, I have to customize web pages which are displayed by WSS 3.0 engine.
Now, the structure of web pages are modified and I have to change the appearance of those, using Cascading Style Sheets (CSS). I copy the original CSS called “core.css” and rename it. I keep it on the original folder. To use it, in SharePoint Designer I defined it as “default masterpage”. With this change, all new websites are automatically using my new masterpage. Now I have to change colors, layout, fonts, background colors, … But be careful! Styles are used everywhere… To find the styles name you can use a web browser toolbar (for ie or firefox). It’s very useful!
Next you can export this site as a template to create a generic model of this site (*.stp == site template). So that you can replicate this website as many time as you want, using you CSS and your modifications.
I hope that this article can help you!