Open Eclipse's preferences. In the menu on the left, navigate to PHP -> PHP Executables. Click the Add button. Under executable path, put the path to the php executable. With a new installation of WAMP, the path is C:\wamp\bin\php\php5.3.0\php.exe
. Click "Finish".
For the server component, navigate to PHP -> PHP Servers in the preferences screen. If "Default PHP Web Server" does not exist or does not point to http://localhost/, click "New" and fill it in.
Take note of the "Path Mapping" tab of each server (accessible by selecting an existing server and pressing "Edit"). This lets you map a local path in your eclipse workspace to specific sub-urls of WAMP. This is useful if you deploy apps into your WAMP installation using VirtualHosts that have separate DocumentRoots.