I would like to know what would be the best software (free) out there that I can use to build websites with multiple different skins or designs? Can anyone offer some suggestions?
I'd say Kompozer.net although there's one out by trellian that's supposed to be good. Just google trellian wysiwyg. Or for larger sites for ease of management Wordpress although it's less flexible it's WAY easier to manage and update. If you're willing to shell out a few bucks then I'd say xsitepro for larger sites.
You can use Joomla Wrodpress etc. Apart from that you can use Dreamweaver from Adobe to build simple web pages. 30 days trial software is available on adobe.com Cheers
I vote for terapad. Its easy to use and impressive SEO friendly news feature. You can signup for a free website first to test how the system works. Their website is www . terapad . com
If you look at the modules for Drupal http://drupal.org/project/Modules you'll see that it is quite versatile software.
You can use Drupal and install a lot of the themes into your site: http://drupal.org/project/themes Then you can switch between them or let your users select which one they like best.