Google Inc. is letting advertisers add a clickable phone number to their mobile ads, making it easy for customers to connect with the local business they are looking for directly by phone.

Google has expanded click-to-call phone numbers for national advertisers. Now advertisers can add a national phone number to the last line of ad text for any existing or new campaigns, making it easy for customers to connect with the business by phone directly from the ad, regardless of their location.

?This can be especially helpful when you're trying to connect with the business call center rather than a specific business location,? said Surojit Chatterjee, product manager of mobile ads at Google, Mountain View, CA, in a blog post.

?After searching for a travel services, for example, you might want to call to discuss trip planning with an agent,? he said. ?Or after searching for car insurance, you might want to call for a quote.

?Now, if you're using an iPhone, Android device, or Palm Pre, you can just click the phone number to call the business without needing to navigate to a new page.?

Here are step-by-step directions for advertisers that want to add a clickable number to their mobile ads:

1. Set up phone extensions and add the business phone number. Customers will be able to click to call a business directly from its ad.

For businesses that have added location extensions to their campaign, they can give each location a different phone number. AdWords will automatically display the business telephone of the nearest location to where the user is.

2. Businesses need to ensure they have chosen to show their ads on iPhones and other mobile devices with full Internet browsers in their campaign settings.

Advertisers can review how many calls they have received for each keyword, ad group, or campaign from the Campaigns page within AdWords.

On the Campaigns, Ad groups or Keywords tabs on the Campaigns page, click the ?Segment? button above the statistics table.

Select ?Click Type? to see which clicks resulted in visits to the businesses Web site or phone calls.

The cost of a click-to-call is the same as the cost of a click-to-Web.

A call is reported as soon as the user clicks on the phone number, regardless of whether or not it is completed. Therefore, if a user cancels a call before it finishes connecting, the advertiser is still charged.