I have a user directory on a domain such as www.something.com/~user/
and I want to be able to both create and access a folder like www.something.com/~user/folder/
In UNIX I can make a directory inside the public_html folder, but I'm currently unable to access it through the URL. I am using an Apache web server. Thank you in advance!
http://httpd.apache.org/docs/current/howto/public_html.html answers your question. Once you've created $HOME/public_html/my/folder and configured your apache webserver appropriately (don't forget to restart it) you will be able to browse to
http://www.something.com/~username/my/folder