Whaddya know how to turn off the targetted ad in Google Apps?

This is only applicable for Google Apps Premier Edition and Education only. You can't turn off the targetted ad in Standard Edition, a free version of Google Apps.

Ok let's begin.

Login to your Google Apps. In your Control Panel (after clicking Manage this domain for administrator), select Domain Settings tab, then scroll down till you see Advertisement option.

Put check on Hide all ads for this domain, click Save changes and you're done.