I upgraded my Mac to Mac OS X Yosemite.
I had a LAMP stack installed and it worked fine.

After upgrading to Yosemite, I got following problem:

when trying to load phpMyAdmin at http://localhost/phpMyAdmin I get the following error:

Forbidden. You don't have permission to access /phpMyAdmin on this server.

First thing I tried to do is to change file permissions in /phpMyAdmin folder to match those of www, but that didn't help.

Since upgrade to Yosemite updated Apache to 2.4, its necessary to manually update phpMyAdmin.conf to use new Access control syntax.
For more info have a look at: http://httpd.apache.org/docs/2.4/upgrading.html

phpMyAdmin.conf is created under /etc/apache2/other/ and contains alias to phpMyAdmin folder.

In my case I needed to change it from:

Order allow,deny
Allow from all

to

Require all granted