For Apache 2.4.2: I was getting 403: Forbidden continuously when I was trying to access WAMP on my Windows 7 desktop from my iPhone on WiFi. On one blog, I found the solution - add Require all granted after Allow all in the <Directory> section. So this is how my <Directory> section looks like inside <VirtualHost>
<Directory "C:/wamp/www">
Options Indexes FollowSymLinks MultiViews Includes ExecCGI
AllowOverride All
Order Allow,Deny
Allow from all
Require all granted
</Directory>