How do I go about adding a blog to my own site and will visitors to my site be able to add their own photos/blog information also? I would like to
add it to my site as an extension like www.mysite.com/blog

Basically, I'm also looking to add a blog section on my website for
visitors to create their own blogs that can be viewed on my site.
(i.e. www.mysite.com/blog/joe) or whatever name they wish.

Please help anyone. Thanks

Please see this tutorial