Are you using apache?
If so, open up the apache config file in your favourite text editor (usually /etc/apache/httpd.conf IME) and look for this stanza:
# UserDir: The name of the directory which is appended onto a user's home
# directory if a ~user request is received.
# UserDir public_html
And uncomment the last two lines, then restart apache.
You can replace public_html with whatever you want to call the folder in your home dir.