set PATH=%PATH%;C:\path\to\php

1. Open control panel
2. Go to System
3. Choose the Properties tab
4. Click Environment variables

From this screen you can edit the environment variables of the system. If you only wish to modify them on your user account, click New under your own variables box and type in the following:

Variable name: Path
Variable value: %PATH%;C:\path\to\php

If you want the change to affect all users on the system, choose the Path variable from the system variables box and click Edit.

Append the variable value with:

;C:\path\to\php

zdroj: http://codeutopia.net/blog/2008/07/28/setting-up-command-line-php-on-windows/

http://coolestguidesontheplanet.com/get-apache-mysql-php-phpmyadmin-working-osx-10-10-yosemite/