Install Homebrew

The first thing you will need to do is install Homebrew. Open up your terminal and run this:

Do not run any of these commands with sudo! Repeat: DO NOT USE sudo!
% ruby -e "$(curl -fsSL https://raw.github.com/Homebrew/homebrew/go/install)"

Pay attention to all the instructions, run the brew doctor command as required, and be sure to configure your PATH afterwards (you might not need to do this).

Install MySQL with Homebrew

OSX does not come with MySQL installed by default, so we will need to install it using Homebrew:

% brew install mysql

Follow all of the instructions that are output by this process, including the parts about securing your database. Once installed you might want to use LaunchRocket.prefPane to manage MySQL and other services you install with Homebrew.

Install PHP with Homebrew

Next you will need to install PHP. Because OSX comes with PHP preinstalled, and Homebrew does not duplicate preinstalled packages, you will need to "tap" a new repository first:

% brew tap josegonzalez/homebrew-php
% brew install php54 php54-http php54-mcrypt

Again, follow all of the instructions that are output by this process. Once successful, you will also want to install composer:

% brew install composer

Installing composer this way is optional, but will ensure that your local version of Composer stays updated when you run brew upgrade.

You should also edit /usr/local/etc/php/5.4/php.ini and set date.timezone to your local timezone. Check the list of supported timezones and choose the one most appropriate.

Enable the Built-in Apache Server

Mac OSX comes with Apache installed by default, but disabled. The easiest way to enable it it is to use WebSharing.prefPane. If you want to start Apache manually, you can use:

sudo apachectl start

To add a new virtual host, you will need to edit the Apache configuration in /etc/apache2. You might want to use either osx-vhost-manager (free) or VirtualHostX (paid) to help manage virtual hosts.

Finished

Once these steps are completed, have you have properly updated your PATH to include /usr/local/bin, you can follow the rest of the install process. Double check that everything is installed properly with:

% php --version
% mysql --version 

You should end up with PHP 5.4.x and MySQL 5.6.x (or higher).

Now Install and Run Ushahidi

Go to Installing Ushahidi 3.x and follow the instructions there, starting with downloading the Ushahidi code.