I want to develop 2 skins for JForum (One for me and another one for free to all). Could anyone tell me exactly what are the files to be modified? (Just for quick sort).
Just take a look in the jforum templates directory. The "default" directory holds the standard JForum look and feel.
You'll need to edit the templates/theme_name/style.css file and the image files in the templates/theme_name/images subdirectory.
The cellpicX.jpg/gif files control the "bars" at the top of the message sections. There is also a language directory (i.e. en_US) under the images dir which has the "post reply" type icon images (containing words).
You can also use the PHP BB themes as a starting point. Most are a close fit.
Then to activate the new theme, edit the WEB-INF/confi/SystemGlobalProperties file to point to the new theme directory (assumed to be under the templates folder).
You don't have to restart anything after editing the SystemGlobalProps file .. the new look will appear automatically.