Here is a list of FREE Blog Templates

WordPress

Short description: WordPress is a Blog tool and Weblog platform. You canyou’re your own wordpress account in seconds or install it on your own domain. Wordpress is easy to use and custmoise and one which I definelt recommend. Thers are hundreds of themes to choose from and plugin that make creating a professional blog so easy. Some of the features include password protected posts, importing, typographical niceties, multiple authors, bookmarklets, permalinks.
Homepage: http://wordpress.org/

Blogger

Short description: Blogger is easy-to-use web site, where you can quickly post thoughts; interact with people, and more.
Homepage: https://www.blogger.com/

b2evolution

Short description: A blog script featuring multiple blogs, categories/sub-categories, skins, search function, multiple languages, search engines friendly URLs.
Homepage: http://b2evolution.net/

Nucleus

Short description: A powerful blog script featuring multiple blogs, multiple authors, drafts and future posts, bookmarklets.
Homepage: http://nucleuscms.org/

pMachine Free

Short description: This is a features limited version of pMachinePro.
Homepage: http://www.pmachine.com/

If you use any other blogging platform and would like to see it listed here then please leave me a comment and I will add it to the list.