anyone have an idea what wordpress plugin these sites are using? http://freewpthemes.co/ http://www.freewpthemes.net/ http://www.freewordpressthemes.com/
These uses wordpress-theme-demo-bar plugin. http://wordpress.org/extend/plugins/wordpress-theme-demo-bar/
That plugin seems to allow the user to view the site with different themes. What I am looking for will allow theme builders to sign up onto the site. Upload their free use themes (normally they use footer links to make money from the theme). If not up load the theme file, them upload all the information about the theme (Tags, colors, description, etc) and then input the link for the theme download (on another site. There would also have to be an administration program that would allow me to delete spammers etc. here is an example of the submit theme page http://wpthemesdir.com/submit-theme/
This is not exactly it, but here is one: http://wordpress.org/extend/plugins/wordpress-theme-showcase-plugin/screenshots/
I think they are using some customized plugin to show the preview of each and every theme. They are also using the same for listing of the theme in this manner.
Ok, you want to build a WordPress theme collection site... which allow guest / registered users to upload themes with details you specified. I don't think there is any specific wordpress plugin for this. But you can get it done custom by hiring a developer.