httpd.conf Activate User Webspace

Load the User Directory module:
LoadModule userdir_module modules/mod_userdir.so

Add the following lines to activate user dirs:
<IfModule mod_userdir.c>
UserDir public_html #typical dir convention is public_html
</IfModule>

Set directory specific options (optional):
<Directory /export/home/*/public_html>
AllowOverride FileInfo AuthConfig Limit
Options MultiViews Indexes SymLinksIfOwnerMatch IncludesNoExec
<Limit GET POST OPTIONS>
Order allow,deny
Allow from all
</Limit>
<LimitExcept GET POST OPTIONS>
Order deny, allow
Deny from all
</LimitExcept>
</Directory>

Several Available Options:
All: all options except multiviews (default)
ExecCGI: Execution of CGI scripts is permitted
Indexes: if no DirectoryIndex (index.html) present in dir, display formated list
SymLinksIfOwnerMatch: follow sym links only if source and target owner match

Several Available AllowOverride directive settings:
This directive allows the use of .htaccess files to override
All: all options are allowed in .htaccess
AuthConfig: allow use of AuthName, AuthType, AuthUserFile, AuthGroupFile, Require, etc.
Indexes: allow use of DirectoryIndex and more
Limit: allow use of Allow, Deny and Order
Options: allow use of specific option settings (above)

http://httpd.apache.org/docs/1.3/mod/core.html#allowoverride