Two way of install plugin

1:
From the Help menu, select Install New Software... to open an Install pop-up window.
In the Work with: text box of the Install window, type the URL http://update1.aptana.org/php/25753/for the update site, and hit the Enter key.
In the populated table below, check the box next to the name of the plug-in, and click the Next button.
Click the Next button to go to the license page.
Choose the option to accept the terms of the license agreement, and click the Finish button.

 

2:
Manual Installation

Download Plugin Update Site
Save the above file to an easy-to-find location.
Open Eclipse distribution, and go to Help -> Install New Software....
Click the Add... button to open the Add Site window.
Click the Archive... button, and select the file saved in step 1.
Select the appropriate plugins to install, and click Next -> Next.
Click the Finish button.